we're facing a problem we can't solve. Fortinet support and Microsoft support also break their teeth on it.
We have a Fortigate 81E, firmware6.2.4. Our users connect in SSL VPN with a Forticlient. This allows them to connect in RDP to different VM servers of the company. They do, however, have problems with frozen displays. If they don't work on the server in RDP, after a while they freeze, and after a few seconds (between 5 and 30 sec) the connection comes back.
A continuous ping test shows that there is no packet loss. The Forticlients have been upgraded, and the MTU of our WAN connection is 1500. And for Microsoft nothing to report on the HyperV side. Finally, no problem found when testing in VPN SSL web mode.
Do you have any idea where this might be coming from?
Thank you for your help