Microsoft POP Support for Emails using OAuth 2.0

Issue Summary

Jira currently only supports IMAP for Microsoft when authenticating using OAuth 2.0. Support should also be enabled for POP. 

Steps to Reproduce

1. Setup Microsoft client configurations in the OAuth 2.0 plugin
2. Navigate to "Incoming Mail" in Application properties
3. Select Microsoft and currently, only IMAP is supported
4. Configure mail handler using Microsoft configuration and POP3 protocol

Expected Results

The newly configured mail handler is working properly and can be saved.

Actual Results

The following error is thrown in the UI on the "Test connection" step:

AuthenticationFailedException: Protocol error. Connection is closed. 10.

Workaround

Currently, there is no known workaround for this behavior. A workaround will be added here when available

Note about the fixed introduced in 8.5.12, 8.13.4 and 8.15.0

For the combination POP + Oauth 2.0 to work in the fixed Jira versions, it is necessary to tick the box Use two line authentication format in the Mail Server configuration before clicking on Test Connection as shown in the screenshot below. Note that this new setting is only available in the Jira versions which introduced the fix: