Notifications not working

[Felipe Seiber]

Our email notifications suddenly stopped working. From my current diagnosis it appears to be an issue with JIRA. For some reason no comments or task changes are going into the mail queue to be sent out. Standard test emails and system wide mail is still working

I've checked the following:

• Mail Queue - unable to resend error or flush the mail queue
• Sent a Test Mail inside the SMTP Server configuration setup screen. 
• System -> Send email works and has no issues using our mail server
• Mail Queue Service is still running
• Reindexing did not resolve the issue
• Disabled the only extra app we have installed "Timesheet Reports"
• Checked notification scheme settings for each project
• Restarting the JIRA service did not resolve the issue
  • This also unfortunately lost all of the emails in the queue... very annoying.... 
  • https://jira.atlassian.com/browse/JRASERVER-4665 
• Restarted the entire server

Can anyone recommend any further troubleshooting steps to try?