Forti VPN and Outlook disconnect

[Andizer]

Hello,

we got some users that are losing there Outlook Client connection after like 1-4 hours.
I have already removed all utm features, but the problem still occurs.

I can see a TCP reset from client but the VPN Tunnel itself stays alive.

Running EMS 7.2.2 and Fortigate 7.0.13

Maybe someone got an idea ?

Best regards

[dbhavsar]

Hello @Andizer ,

- Can you please confirm that when outlook disconnects is it giving any certificate warning to the users also users are on Windows 10/11?

[Andizer]

Hello,

yes we use windows 10 and we dont get any certificate warnings.
This problem only occurs with some users, around 40 out of 1000 users.

Best regards

[dbhavsar]

Hi @Andizer ,

Not sure if this could help I found this from Microsoft using Windows 10.
https://support.microsoft.com/en-gb/topic/february-27-2020-kb4535996-os-builds-18362-693-and-18363-6...

- Can you try one of the machine upgrading to windows 11 and see if the issue persists or not?

[Andizer]

Hello,
unfortunately, this is not a valid option for us. All other programs work, even Outlook web access works. Only the outlook client doesn't work.

Best regards

[Andizer]

Is there even a version that can be used? Fortinet turns its customers into beta testers. After months of problems and bugs, we are about to drop the software and accept defeat.

[btan]

Hello there,

Do you already have a TAC ticket opened with us? We will have to collect FCT_Diagnostic_Result to see if there is any clues regarding this issue.
You mentioned that all utm is already turned off (AV, AppFW, WF), it would be very weird if somehow FCT is still the root cause. Please attach your XML config file to your TAC ticket for TAC to assist on this.

[Andizer]

As soon as we let affected users run a mobile hotspot, everything works. If he uses his home Vodafone internet connection, he immediately has problems. This behavior can be recreated with several affected users. The same Internet connection when used with Cisco Anyconnect VPN causes no problems and works. Could it be that the internet provider Vodafone has problems with Fortinet but not with Cisco Anyconnect?

Weird

Regards