1. Is the message reaching the e-mail account?

Have your mail server administrator confirm that e-mail sent to the account JIRA is using is successfully reaching the account's Inbox.

2. Is the Create Or Comment Handler service configured correctly in JIRA?

Please review this guide to confirm this:

メールから課題およびコメントを作成する

3. Are permissions set properly?

Does the user submitting the issue have Create Issue permissions in the Permission Scheme? If you are having troubles adding comments, make sure your Issue Security Scheme is not restricting the user's access to the issue.

4. Still not working? Enable debug logging in JIRA:

First, we need to change the com.atlassian package from the WARN logging level to DEBUG. This can be done from the following menu:

Administration -> System -> Logging & Profiling -> Click Edit next to the com.atlassian package

5. Send two e-mails to the email address that JIRA is checking for new issues and comments. Wait 5 minutes and then submit a support request that includes the JIRA logs.

This can be done from the following menu:

Administration -> System -> Support Request

Remember to check the Attach JIRA logs box! Also, please note the e-mail address being used for testing and copy/paste the JIRA service settings for this Create Or Comment handler:

Administration -> System -> Services

6. Change com.atlassian back from DEBUG to WARN.

Administration -> System -> Logging & Profiling -> Click Edit next to the com.atlassian package

WARNING: Leaving com.atlassian in debug mode will result in VERY large log files!

Note. If you want to log on a protocol level (IMAP, POP3 or SMTP), please refer to Logging email protocol details.