We've recently moved from an ancient 3.0 version of OTRS to 6.0.10 (+ ITSM). Following this move, we're having problems getting auto-responses generated from some inbound emails. All our emails are handled by OTRS from a single IMAP mailbox, but arrive at that mailbox from a series of routes and with different 'To:' addresses. OTRS uses the System Email address to dispatch to a particular queue, and that queue has auto responses set. For some inbound messages we also use Postmaster Filters to direct tickets to particular queues, and set X-OTRS-Loop to 'true' where relevant to stop auto-responses. Some of our mails arrive at the OTRS mailbox after being redirected via an Office 365 mailbox, and it's these mails that are no longer generating an auto-response - this used to work on the OTRS 3.0 system. Instead, when looking at the ticket history, we are seeing this information message: Sent no auto-response because the sender doesn't want an auto-response (e. g. loop or precedence header) (Misc) However, as far as we can tell, no postmaster filters are being invoked, and this inbound email doesn't have any headers that would seem to trigger this behaviour. There's certainly no X-OTRS-Loop header, or 'Precedence' header. I've sanitised the received headers for a an email that triggers this behaviour - I've removed the header values but the attached file shows what headers are included. If a mail is directed straight at the OTRS mailbox rather than having to be re-directed via the Office 365 mailbox, the auto-responses get generated as expected (unless intentionally blocked by a postmaster filter). This suggests that maybe Office 365 is putting in some extra headers that trigger the warning. 1) Is there any way to check whether any postmaster filters ARE being invoked for a specific ticket - this used to be in the logs but I can't spot it in the OTRS 6 communication logs or elsewhere. 2) Is there any obvious header in the attached file that might trigger this issue? 3) Is there any Sysconfig option that might alter this behaviour? Thanks Phil ________________________________ This message (and any attachments) is for the recipient only. NERC is subject to the Freedom of Information Act 2000 and the contents of this email and any reply you make may be disclosed by NERC unless it is exempt from release under the Act. Any material supplied to NERC may be stored in an electronic records management system. ________________________________