No shares are being submitted, which is kind of weird.
It is... about half the people connected have that issue, the other half seems to be working fine... Can you tell me which miner you're using? I use sgminer5 and it seems to work fine but maybe there is a problem with the pool causing trouble with some other miner...
sgminer 4.1.0
I just did a quick research and found this page:
http://www.groestlcoin.org/pools/saying you have to use this: --difficulty-multiplier 0.00390625
Maybe that's the issue and some miners like sgminer 5 implement it by default or something...
Let me know if that helps!