Problem Definition

Before the release of JIRA 7, users without the JIRA Users Global Permission were not able to log in to JIRA, but if they belonged to a group that had Create Issue permission for a project, they could create issues via email if a JIRA email handler was set up, as documented here: https://confluence.atlassian.com/display/JIRA/Creating+Issues+and+Comments+from+Email

In JIRA 7, a user must have access to at least one JIRA application (JIRA Software, JIRA Service Desk, or JIRA Core) in order to create issues, regardless of how the issue is created. This means that any user that is not able to log in to JIRA and create an issue via the Create Issue dialog will not be able to create issues via a JIRA email handler. This changes caused the existing JIRA Mail Handlers to throw messages when performing a test run.

Suggested Solution

Allow the users without application access to create issue via email if they belong to a group that has permission to create issue in JIRA.

Workaround

Set up anonymous issue creation as documented here and change the email addresses of users being deleted or disabled so they are not matched by the mail handler: JRA-33116

Another workaround would be to have a "Forward Email" address in the mail handler so you are notified on failing emails and users can be manually enabled or created.