VoteCoin activated overwinter (new protocol) after block 179999.
When this happened, most mining pools (including the official pool) stopped working.
For some reason the most commonly used pool software (z-nomp) creates blocks which are refused by the network.
In my opinion it is necessary to patch the z-nomp software for the overwinter update, unfortunately I didn't find anything useful yet.
If you have any suggestions, please be so kind and share them here.
Thank you very much
-Tom