FortiMail - Office 365 outbound

[rashley]

We recently implemented a FortiMail appliance to handle our Office 365 spam/AV filtering.  We started noticing an issue with outbound email to a number of random domains, where they would get a "Too many hops" error and never get delivered.

Inbound email through FortiMail seems fine and the majority of outbound email also seems fine, but there was at least 6 customers we could not email because of the too many hops error.  They all seemed to be other Office 365 customers, but it's possible some were not.

For now, we have removed the rule and connector so outbound email is back to using Office 365 directly.  Inbound email is still being filtered by FortiMail.

Has anyone else seen these "Too many hops" error when outbound email is going through the FortiMail, specifically in an Office 365 configuration??  Actual error below:

"Too many hops 31 (30 max)"

[Bromont_FTNT]

We've seen this on outbound mail where the recipients MX record is also Office 365. The Fortimail sends outbound mail to the OutlookProtection servers as it should but they send it back to the Fortimail for some reason. This is really a question for Microsoft as to why they are sending mail back.