The configuration option to look at is the one identified in the
You can read about it in your RT_Config or here:
Something about the incoming message is causing RT to
I have narrowed down the issue to being a missing configuration with RT
permissions - not an issue with any ISP in particular.
If a reply is sent via a mail client, RT logs this message...
 [Tue Mar 29 15:46:51 2016] [info]:
I'm experiencing an issue with a particular queue where by a Hotmail
address requester does not get email notifications if their ticket is
replied to via a mail client - RT gets updated with the reply but it
doesn't send out an email to the requester. If the same ticket is