[Server issue] invalid steam key size

[WNxKraid]

Today i managed to get a dedicated server up and running for Goldeneye Source Beta 3.1 (also OB engine).
It showed up on the internet tab and other ppl saw it, too.
Which i was really exited about coz i thought now i can run a PV server, tried it and... i was wrong.

For some reason if someone wants to join the server, he'll get a "invalid steam key size" message.
I remember that's an issue we had with GES, too.
Short after the release of beta 3 valve broke the OB Servers so any updated server wasn't displayed on the internet Tab of the serverlist anymore and updated clients couldn't join.

There were some semi workarrounds but i guess it was never solved completly.
Luckly GES got an update/patch to vers. 3.1 and the problem was gone.

But now i stumbled across this issue again.

So i would like to ask, if there is anyone who might be able to help me to solve this problem.