The current pre-release of the client ("pioneer" in the version) is only compatible to itself. So you can only play with other testers. Please be aware!
So, I turned on IPV6 in FAF settings, choose COTURN server Finland (no server was chosen before), turned on experimental debugger. And it started connecting 80-90% times (it's ok for me, because it was around 0% for the last week and much earlier). Maybe this information will help somebody.
