No in/out using FortiMail

Good day!

I’m working on POC right now with some minor issues. J

Please Existing Setup and the proposed one.

Existing setup their Exchange server running on 2 NIC cards, one is private facing LAN and the remaining one is facing public.

On the proposed setup, take out the NIC facing Public, do VIP (a.b.c.90-->192.168.0.31) to my Fortigate pointing to my Fortimail device ip address. Configured my Fortimail via wizard using Gateway mode. So far Fortimail able to received emails and handover to Exchange Server….but email clients unable to Send/receive emails.

It’s so unfortunate me and end user don’t have much skill set in managing Exchange servers. I'm done with FortiMail config. Is there or what possible settings in Exchange Server do we need to configure?

In my previous implem/poc wizard is my tool and everything works perfectly. J

Any inputs is much appreciated. :)

/Regards