It appears that lately TM might have fiddled with their router settings resulting in a MTU error. This however should be applicable to anyone who has problems holding a VPN connection when transferring through it.
Browse to your OpenVPN config folder (where you store your certificates and .ovpn files) and pick a configuration file that you wish to test with (for e.g. PrivateTracker.ovpn).
Open this up in notepad and add the statement:
in a new line AFTER the line that says ‘proto udp’.
Restart and see if it improves stability. If it doesn’t you can also try mssfix values of 1200 or 1300.