I have spent the last few weeks troubleshooting this issue with FortiGate Support and they have confirmed that it is not the FortiGate that is causing these issues.

I have opened another ticket with Support a few weeks ago but there has not been any progress so far. We have started with FortiGate/FortiClient 5.4.x and upgrading to different versions (which is something Support always likes to suggest) has made zero difference. Is anyone else experiencing this? Are there any recommendations to make the FortiClient more resilient in this regard? This issue has been bugging us for almost three years. This therefore points to the FortiClient itself. So I don't think the problem lies there.ДЄll users connect to the same IPsec dialup tunnel (ike=1, authentication=psk, mode=aggressive, lifetime=86400/43200,В dpd-retrycount=3,В dpd-retryinterval=15)В and since this is not affecting everyone, I guess we can rule out an issue on the FortiGate too. I have experienced frequent disconnects myself on my ADSL home Internet link whereas I don't experience any disconnects anymore now that I am on fibre.В All workstations are set up using an image and are therefore identical in the way they are configured. In my experience, the quality of the Internet link makes a big difference. For the majority of our users the FortiClient connection is pretty stable. This does not affect all of of our users. Even if there was packet loss for a moment, it must have been very brief. The connection simply drops while they are working, and for no apparent reason as applications such as Skype, Teams etc. Some users have to reconnect more than 10 times a day. Some of our user's FortiClient IPsec VPN connection (Windows 10 ењ†4, FortiClient 6.0.9, FortiGate 6.0.9) drops numerous times a day.

Ncp secure entry client disconnecting