Symptoms

The @mention feature (as from Emailing an Issue) does not work as expected, with one or more of the following symptoms:

1. @mention does not populate username
2. Pressing Enter to auto-complete a username does not work
3. The mentioned username does not appear properly as the user's display name, but as [~username]
4. No email is sent to the mentioned user

Cause

Here're possible causes for each of the above symptoms:

1. There're 2 possible causes:
   1. The user who is trying to mention another user does not have Browse Users global permission, which is required to browse (populate) users
   2. A bug as reported in JRASERVER-28081 - @Mention failed if the user mail visibility is set to Hidden
2. This is caused by Zephyr plugin, as reported in JRASERVER-41358 - @ Mention used to allow selection w/ Enter key - now needs mouse click
3. The field where the user is being mentioned is not using Wiki Style Renderer
4. There're several possible causes for this:
   1. the outgoing mail server is not functioning
   2. the mentioned user does not have Browse Project permission
   3. the issue where he's being mentioned has a security level that restricts him from viewing it
5. There is an empty Recipient against one of the Notification Events (a notification event is set up to have a recipient, but is blank) on the Notification Scheme page.

Resolution

1. For:
   1. Ensure that the user has Browse User global permission, as in Managing Global Permissions
   2. Upgrade JIRA to 6.1.1 or above
2. Check out the bug ticket for more information

3. Ensure that the field is using the Wiki Style Renderer, as in Configuring Renderers

4. Ensure the outgoing mail server is working properly and the mentioned user is able to view the issue
5. Delete any empty Recipients against a Notification Event