It seems the pool recently died.
Yesterday, at about 2am UTC, the sha-256 pool EU stratum server died and with it block confirmations and payouts stopped. Later in the day the sha-256 pool US stratum server died, too. Individual coin servers are still running, but without block confirmations...
Over the last days I noticed some other strange behaviors, e.g. MZC never built any balance, even though I definitely had shares and the pool reported found blocks.
Luckily the only thing I had pointing there were 2 lonely antminer U2s