Bad encapsulated packet warning

Pritunl Pritunl VPN
1

I’m getting this error message in the server logs:

WARNING: Bad encapsulated packet length from peer (5635), which must be > 0 and <= 1627 – please ensure that --tun-mtu or --link-mtu is equal on both peers – this condition could also indicate a possible active attack on the TCP link – [Attempting restart…]

2

Try lowering the Connection MTU in the server settings to 1300.

3

Is there anyway to fix that on the free version?
Like editing a file or any special command?
I tired some various changes, none of them has worked, I’m still stuck with this problem.

4

There’s no other way to set it. That would only rule out an issue with detecting the MTU. But with a packet length of 5635 it’s likely some other issue with the server configuration, I don’t have enough information to debug that issue.