the pool is down?
or just credential is invalid, maybe you are not even mining, but just "stratum detecting new block"
I'm mining an alt coin and the coins show it;s just it stops and then I have to start the bfgminer again
C:\Users\Nate\Documents\cg\bfg\bfgminer.exe -o
http://127.0.0.1:21004 -u nate -p bghgje -S antminer:all --set-device antminer:clock=x0A81