I actually quit mining there for that same issue on the ZEC pool. First miner could connect then I could never connect a second. I tried to go through their support, someone other than OC was responding but he seemed to think the problem was on my end. He never fixed it so I just moved pools.
I Am using flypool for now but i prefer supernova.
it was working great till yesterday when I wake up i found it not connecting i need to know why it's giving this error.