Problem with Norton 360 and Proton VPN

I have a testbed where I run Proton VPN and also have to run Norton 360. Unfortunately I can not establish a VPN connection as long as Norton 360 is running. Deactivating Norton Firewall solves the issue, but this is no solution as I have to run Norton 360.

Proton VPN jumps always between “Waiting for network” “Initialising…”. Sometimes it works, but 9 out of 10 fail.

Any idea/solution?