VPN L2TP unstable - packets won't reach internal machines sometimes

Hello,

I have a strange behavior lately with a Mikrotik router using at the time 6.36 and now 6.36.3
On both version, same issue.

It could be an unstable pppoe issue but it seems more likely to be a VPN issue as I am still connected to the VPN when it happens.

I have set up an L2TP connection on a router which use to work well since months but the last few days, it connects right away, I can ping or access machines inside the network and then the packets won’t reach the machines inside the network anymore.
I tried 2 different machines in the same network, no ping, no access.

However I am still connected to the VPN and can ping the gateway with the internal IP address.
But it is like the routes are lost…

Sometimes after a little while, it works again but then stop again.
Usually it would work for a few seconds.

I thought it could be the internet connection where I am connected but it works fine on another router in a different company (L2TP on mikrotik as well)

Any hint on where to begin?

Dear guys,

I need your help here. It starts to be really annoying.

Please let me know if you need more informations or logs.
So far, I’ve checked them and nothing looks wrong to me.

Thanks in advance.