diff --git a/src/core/features/comments/pages/viewer/viewer.html b/src/core/features/comments/pages/viewer/viewer.html
index 95127219c..94ed52d8d 100644
--- a/src/core/features/comments/pages/viewer/viewer.html
+++ b/src/core/features/comments/pages/viewer/viewer.html
@@ -86,7 +86,7 @@
                 </ion-item>
             </ng-container>
 
-            <ion-item *ngIf="offlineComment" class="ion-text-wrap addon-message addon-message-mine">
+            <ion-item *ngIf="hasOffline" class="ion-text-wrap addon-message addon-message-mine">
                 <ion-label>
                     <!-- User data. -->
                     <p class="ion-text-center">
@@ -94,7 +94,7 @@
                         {{ 'core.thereisdatatosync' | translate:{$a: 'core.comments.comments' | translate | lowercase } }}
                     </p>
 
-                    <div class="addon-message-text">
+                    <div class="addon-message-text" *ngIf="offlineComment">
                         <core-format-text [text]="offlineComment.content" [contextLevel]="contextLevel" [contextInstanceId]="instanceId"
                             [courseId]="courseId">
                         </core-format-text>
@@ -104,7 +104,7 @@
                     <ion-icon name="fas-clock" aria-hidden="true"></ion-icon> {{ 'core.notsent' | translate }}
                 </ion-note>
                 <div class="tail"></div>
-                <ion-button *ngIf="showDelete" slot="end" fill="clear" [@coreSlideInOut]="'fromRight'" color="danger"
+                <ion-button *ngIf="showDelete && offlineComment" slot="end" fill="clear" [@coreSlideInOut]="'fromRight'" color="danger"
                     (click)="deleteComment($event, offlineComment)" [attr.aria-label]="'core.delete' | translate"
                     class="addon-messages-delete-button">
                     <ion-icon name="fas-trash" slot="icon-only" aria-hidden="true"></ion-icon>
diff --git a/src/core/features/comments/pages/viewer/viewer.page.ts b/src/core/features/comments/pages/viewer/viewer.page.ts
index dc371bb13..6e46394cf 100644
--- a/src/core/features/comments/pages/viewer/viewer.page.ts
+++ b/src/core/features/comments/pages/viewer/viewer.page.ts
@@ -222,13 +222,15 @@ export class CoreCommentsViewerPage implements OnInit, OnDestroy {
      * @param infiniteComplete Infinite scroll complete function. Only used from core-infinite-loading.
      * @return Resolved when done.
      */
-    loadPrevious(infiniteComplete?: () => void): Promise<void> {
+    async loadPrevious(infiniteComplete?: () => void): Promise<void> {
         this.page++;
         this.canLoadMore = false;
 
-        return this.fetchComments(true).finally(() => {
+        try {
+            await this.fetchComments(true);
+        } finally {
             infiniteComplete && infiniteComplete();
-        });
+        }
     }
 
     /**
diff --git a/src/core/features/comments/tests/behat/basic_usage.feature b/src/core/features/comments/tests/behat/basic_usage.feature
new file mode 100644
index 000000000..1821e2b06
--- /dev/null
+++ b/src/core/features/comments/tests/behat/basic_usage.feature
@@ -0,0 +1,323 @@
+@core @core_comments @app @javascript
+Feature: Test basic usage of comments in app
+  In order to participate in the comments while using the mobile app
+  As a student
+  I need basic comments functionality to work
+
+  Background:
+    Given the following "users" exist:
+      | username | firstname | lastname | email |
+      | teacher1 | Teacher | teacher | teacher1@example.com |
+      | student1 | Student | student | student1@example.com |
+    And the following "courses" exist:
+      | fullname | shortname | category |
+      | Course 1 | C1 | 0 |
+    And the following "course enrolments" exist:
+      | user | course | role |
+      | teacher1 | C1 | editingteacher |
+      | student1 | C1 | student |
+    And the following "activities" exist:
+      | activity | name          | intro                | course | idnumber  | mainglossary | allowcomments | assessed   | scale |
+      | glossary | Test glossary | glossary description | C1     | gloss1    | 1            | 1             | 1          | 1     |
+    And the following "activities" exist:
+      | activity | name      | intro        | course | idnumber | comments |
+      | data     | Data      | Data info    | C1     | data1    | 1        |
+
+  Scenario: Add comments & Delete comments (database)
+    # Create database entry and comment as a teacher
+    Given I entered the data activity "Data" on course "Course 1" as "teacher1" in the app
+    And I press "Information" in the app
+    And I press "Open in browser" in the app
+    And I switch to the browser tab opened by the app
+    And I log in as "teacher1"
+    And I add a "Text input" field to "Data" database and I fill the form with:
+        | Field name | Test field name |
+        | Field description | Test field description |
+    And I press "Save"
+    And I close the browser tab opened by the app
+    When I entered the course "Course 1" as "teacher1" in the app
+    And I press "Data" in the app
+    And I press "Add entries" in the app
+    And I set the field "Test field name" to "Test" in the app
+    And I press "Save" in the app
+    And I press "More" in the app
+    And I press "Comments (0)" in the app
+    And I set the field "Add a comment..." to "comment test teacher" in the app
+    And I press "Send" in the app
+    Then I should find "Comment created" in the app
+    And I should find "comment test teacher" in the app
+
+    When I press the back button in the app
+    And I should find "Comments (1)" in the app
+
+    # Create and delete comments as a student
+    Given I entered the data activity "Data" on course "Course 1" as "student1" in the app
+    And I press "More" in the app
+    And I press "Comments (1)" in the app
+    And I set the field "Add a comment..." to "comment test student" in the app
+    And I press "Send" in the app
+    Then I should find "Comment created" in the app
+    And I should find "comment test teacher" in the app
+    And I should find "comment test student" in the app
+
+    When I press the back button in the app
+    And I press "Comments (2)" in the app
+    And I press "Toggle delete buttons" in the app
+    And I press "Delete" near "comment test student" in the app
+    And I press "Delete" near "Cancel" in the app
+    Then I should find "Comment deleted" in the app
+    And I should find "comment test teacher" in the app
+    But I should not see "comment test student"
+
+    When I press the back button in the app
+    Then I should find "Comments (1)" in the app
+
+  Scenario: Add comments offline & Delete comments offline & Sync comments (database)
+    Given I entered the data activity "Data" on course "Course 1" as "teacher1" in the app
+    When I press "Information" in the app
+    And I press "Open in browser" in the app
+    And I switch to the browser tab opened by the app
+    And I log in as "teacher1"
+    And I add a "Text input" field to "Data" database and I fill the form with:
+        | Field name | Test field name |
+        | Field description | Test field description |
+    And I press "Save"
+    And I close the browser tab opened by the app
+
+    Given I entered the data activity "Data" on course "Course 1" as "teacher1" in the app
+    Then I press "Add entries" in the app
+    And I set the field "Test field name" to "Test" in the app
+    And I press "Save" in the app
+    And I press "More" in the app
+    And I press "Comments (0)" in the app
+    And I switch offline mode to "true"
+    And I set the field "Add a comment..." to "comment test" in the app
+    And I press "Send" in the app
+    Then I should find "Data stored in the device because it couldn't be sent. It will be sent automatically later." in the app
+    And I should find "There are offline comments to be synchronised." in the app
+    And I should find "comment test" in the app
+
+    When I press the back button in the app
+    And I press "Comments (0)" in the app
+    And I switch offline mode to "false"
+    And I press "Display options" in the app
+    And I press "Synchronise now" in the app
+    And I close the popup in the app
+    Then I should find "comment test" in the app
+    But I should not see "There are offline comments to be synchronised."
+
+    When I press the back button in the app
+    And I press "Comments (1)" in the app
+    And I switch offline mode to "true"
+    And I press "Toggle delete buttons" in the app
+    And I press "Delete" in the app
+    And I press "Delete" near "Cancel" in the app
+    Then I should find "Comment deleted" in the app
+    And I should find "There are offline comments to be synchronised." in the app
+    And I should find "Deleted offline" in the app
+    And I should find "comment test" in the app
+
+    When I press the back button in the app
+    And I press "Comments (1)" in the app
+    And I switch offline mode to "false"
+    And I press "Display options" in the app
+    And I press "Synchronise now" in the app
+    And I close the popup in the app
+    Then I should not see "There are offline comments to be synchronised."
+    And I should not see "comment test"
+
+    When I press the back button in the app
+    And I should find "Comments (0)" in the app
+
+  Scenario: Add comments & delete comments (glossary)
+    # Create glossary entry and comment as a teacher
+    Given I entered the glossary activity "Test glossary" on course "Course 1" as "teacher1" in the app
+    And I press "Add a new entry" in the app
+    And I set the field "Concept" to "potato" in the app
+    And I set the field "Definition" to "The potato is a root vegetable native to the Americas, a starchy tuber of the plant Solanum tuberosum, and the plant itself, a perennial in the family Solanaceae." in the app
+    And I press "Save" in the app
+    And I press "potato" in the app
+    And I press "Comments (0)" in the app
+    And I set the field "Add a comment..." to "comment test teacher" in the app
+    And I press "Send" in the app
+    Then I should find "Comment created" in the app
+    And I should find "comment test teacher" in the app
+    And I press the back button in the app
+    And I should find "Comments (1)" in the app
+
+    # Create and delete comments as a student
+    When I entered the course "Course 1" as "student1" in the app
+    And I press "Test glossary" in the app
+    And I press "potato" in the app
+    And I press "Comments (1)" in the app
+    And I set the field "Add a comment..." to "comment test student" in the app
+    And I press "Send" in the app
+    Then I should find "Comment created" in the app
+    And I should find "comment test teacher" in the app
+    And I should find "comment test student" in the app
+
+    When I press the back button in the app
+    And I press "Comments (2)" in the app
+    And I press "Toggle delete buttons" in the app
+    And I press "Delete" near "comment test student" in the app
+    And I press "Delete" near "Cancel" in the app
+    Then I should find "Comment deleted" in the app
+    And I should find "comment test teacher" in the app
+    But I should not see "comment test student"
+
+    When I press the back button in the app
+    And I should find "Comments (1)" in the app
+
+  Scenario: Add comments offline & Delete comments offline & Sync comments (glossary)
+    Given I entered the glossary activity "Test glossary" on course "Course 1" as "teacher1" in the app
+    And I press "Add a new entry" in the app
+    And I set the field "Concept" to "potato" in the app
+    And I set the field "Definition" to "The potato is a root vegetable native to the Americas, a starchy tuber of the plant Solanum tuberosum, and the plant itself, a perennial in the family Solanaceae." in the app
+    And I press "Save" in the app
+    And I press "potato" in the app
+    And I press "Comments (0)" in the app
+    And I switch offline mode to "true"
+    And I set the field "Add a comment..." to "comment test" in the app
+    And I press "Send" in the app
+    Then I should find "Data stored in the device because it couldn't be sent. It will be sent automatically later." in the app
+    And I should find "There are offline comments to be synchronised." in the app
+    And I should find "comment test" in the app
+
+    When I press the back button in the app
+    And I press "Comments (0)" in the app
+    And I switch offline mode to "false"
+    And I press "Display options" in the app
+    And I press "Synchronise now" in the app
+    And I close the popup in the app
+    Then I should find "comment test" in the app
+    But I should not see "There are offline comments to be synchronised."
+
+    When I press the back button in the app
+    And I press "Comments (1)" in the app
+    And I switch offline mode to "true"
+    And I press "Toggle delete buttons" in the app
+    And I press "Delete" in the app
+    And I press "Delete" near "Cancel" in the app
+    Then I should find "Comment deleted" in the app
+    And I should find "There are offline comments to be synchronised." in the app
+    And I should find "Deleted offline" in the app
+    And I should find "comment test" in the app
+
+    When I press the back button in the app
+    And I press "Comments (1)" in the app
+    And I switch offline mode to "false"
+    And I press "Display options" in the app
+    And I press "Synchronise now" in the app
+    And I close the popup in the app
+    Then I should not see "There are offline comments to be synchronised."
+    And I should not see "comment test"
+
+    When I press the back button in the app
+    And I should find "Comments (0)" in the app
+
+  Scenario: Add comments & Delete comments (blogs)
+    # Create blog as a teacher
+    Given the following "blocks" exist:
+      | blockname        | contextlevel | reference | pagetypepattern | defaultregion | configdata |
+      | blog_menu        | Course       | C1        | course-view-*   | site-pre      |            |
+    And I entered the course "Course 1" as "teacher1" in the app
+    And I press "Course summary" in the app
+    And I press "Open in browser" in the app
+    And I switch to the browser tab opened by the app
+    And I log in as "teacher1"
+    And I click on "Open block drawer" "button"
+    And I click on "Add an entry about this course" "link" in the "Blog menu" "block"
+    And I set the following fields to these values:
+      | Entry title | Blog test |
+      | Blog entry body | Blog body |
+    And I press "Save changes"
+    And I close the browser tab opened by the app
+
+    # Create and delete comments as a student
+    When I entered the app as "student1"
+    And I press the more menu button in the app
+    And I press "Site blog" in the app
+    Then I should find "Blog test" in the app
+    And I should find "Blog body" in the app
+
+    When I press "Comments (0)" in the app
+    And I set the field "Add a comment..." to "comment test" in the app
+    And I press "Send" in the app
+    Then I should find "Comment created" in the app
+    And I should find "comment test" in the app
+
+    When I press the back button in the app
+    And I press "Comments (1)" in the app
+    And I press "Toggle delete buttons" in the app
+    And I press "Delete" in the app
+    And I press "Delete" near "Cancel" in the app
+    Then I should find "Comment deleted" in the app
+    But I should not see "comment test"
+
+    When I press the back button in the app
+    Then I should find "Comments (0)" in the app
+
+  Scenario: Add comments offline & Delete comments offline & Sync comments (blogs)
+    # Create blog as a teacher
+    Given the following "blocks" exist:
+      | blockname        | contextlevel | reference | pagetypepattern | defaultregion | configdata |
+      | blog_menu        | Course       | C1        | course-view-*   | site-pre      |            |
+    And I entered the course "Course 1" as "teacher1" in the app
+    And I press "Course summary" in the app
+    And I press "Open in browser" in the app
+    And I switch to the browser tab opened by the app
+    And I log in as "teacher1"
+    And I click on "Open block drawer" "button"
+    And I click on "Add an entry about this course" "link" in the "Blog menu" "block"
+    And I set the following fields to these values:
+      | Entry title | Blog test |
+      | Blog entry body | Blog body |
+    And I press "Save changes"
+    And I close the browser tab opened by the app
+
+    # Create and delete comments as a student
+    When I entered the app as "student1"
+    And I press the more menu button in the app
+    And I press "Site blog" in the app
+    Then I should find "Blog test" in the app
+    And I should find "Blog body" in the app
+
+    When I press "Comments (0)" in the app
+    And I switch offline mode to "true"
+    And I set the field "Add a comment..." to "comment test" in the app
+    And I press "Send" in the app
+    Then I should find "Data stored in the device because it couldn't be sent. It will be sent automatically later." in the app
+    And I should find "There are offline comments to be synchronised." in the app
+    And I should find "comment test" in the app
+
+    When I press the back button in the app
+    And I press "Comments (0)" in the app
+    And I switch offline mode to "false"
+    And I press "Display options" in the app
+    And I press "Synchronise now" in the app
+    And I close the popup in the app
+    Then I should find "comment test" in the app
+    But I should not see "There are offline comments to be synchronised."
+
+    When I press the back button in the app
+    And I press "Comments (1)" in the app
+    And I switch offline mode to "true"
+    And I press "Toggle delete buttons" in the app
+    And I press "Delete" in the app
+    And I press "Delete" near "Cancel" in the app
+    Then I should find "Comment deleted" in the app
+    And I should find "There are offline comments to be synchronised." in the app
+    And I should find "Deleted offline" in the app
+    And I should find "comment test" in the app
+
+    When I press the back button in the app
+    And I press "Comments (1)" in the app
+    And I switch offline mode to "false"
+    And I press "Display options" in the app
+    And I press "Synchronise now" in the app
+    And I close the popup in the app
+    Then I should not see "There are offline comments to be synchronised."
+    And I should not see "comment test"
+
+    When I press the back button in the app
+    Then I should find "Comments (0)" in the app