Unstable Client-2-Site IPSEC VPN --- but only from france to germany

[tobisfr]

Hi,

we are using IPSEC Client-to-Site connections to our company located in germany.

- FG200E   V5.6.12

- Win10 Clients with FortiClient 6.0.10

- VPN Connection created with the "Dialup FortiClient" template

- all clients have the same FortiClient Configuration  (except username ;)  )

The connection from all german clients is fast and stable. No disconnects.

But all connections from france are unstable. The clients are disconnecting 1-2 times per hour.

Does anyone have a similar problem or suggestions why this happens?

Regards 

Tobi