Unfortunately, eu1 and us1 servers of ethermine were very unstable earlier today, which doesn't happen often. The problem was exacerbated by the fact that we are using ethermine.org almost exclusively for devfee on Ethereum, so even when another pool is used, the devfee will fail and cause some errors. The issue was that once you try to make a new connection, the pool closes both the new connection and the existing connection, so we were affected more than some other miners that don't use ethermine.org for devfee.

It seems that now the servers are stable.

On our part we are changing the devfee code to fall back to other pools if ethermine is inaccessible but this will help only if you have other fallback pools besides ethermine.org for the rare occasions when it is down or unstable. The beta version of PhoenixMiner 2.5 will be released tomorrow and it will address most of the stability issues.