VPN Communication issue after FortiWiFi 60D firmware upgrade

[dbilbie]

I have 3 sites:- Site 1 = FortiWifi 60D Site 2 = FortiWifi 60D Site 3 = pfsense I have IPsec tunnel mode VPN’s setup between them all and all have Windows DC’s connected. Everything has been absolutely fine. Except on Friday I decided to upgrade the Firmware on both of the FortiGate devices to the latest and greatest. When everything came back up, the VPN between Site 1 and Site 3 had dropped and I couldn’t get it back up. Eventually I deleted them both and recreated them and all is back to normal. The VPN between Site 2 and Site 3 was up and both networks could ping each other. But I noted in the Windows logs that AD wasn’t syncing between them if they tried to sync off each other. So I logged onto the both and tried to UNC onto their shared drives \\site1share but all I get back from each of them was that Windows couldn’t connect and RPC had failed. Site 1 and Site 2 VPN is spot on (both FortiGate devices) so I deleted Site 2 and Site 3 VPN and recreated it also. This is back up and running but the communication issue still exists between them both. Has anyone has this issue when upgrading the FortiGate devices before? Obviously it only is between the pfsense and FortiGate devices and has only happened since the FortiGate firmware upgrade. Any help would be most appreciated. P.S. I have read somewhere that when using FortiGate and pfsense to use IPsec Interface mode and not tunnel mode. But the fact is tunnel mode has been working correctly before the Firmware upgrade.