Google translate French to English :

I have a hosted remote server that serves as my VPN server, but my internet connections aren't routed through it.
I recently purchased an Archer MR600 to replace a TL-MR6400 that I installed in another home.
I haven't changed anything in my configuration, and since installing the MR600, I've been unable to connect via SSH, HTTPS, or any other method to my VPN server, whereas I had no problems with the MR6400. After a lot of research, I was able to deduce that it was an MTU issue, and the problem was resolved by configuring the OpenVPN server with:
tun-mtu 1340
mssfix 1300
But I don't think it's normal to get to this point, and you still need to have control over the VPN server, and I'm sure many users won't be able to get out of it.