There's a network issue at one of our providers currently, which is affecting the website and may cause intermittent packet loss to stratum servers as well. I'm in contact with them about it, and will post an update when I have more information or have resolved it.
Just fyi, the problem is definitely affecting the pools (at least the X11 pools) as well the website. Here's what I've been getting for the past hour or so...
[19:35:16] No servers were found that could be used to get work from.
[19:35:16] Please check the details from the list below of the servers you have input
[19:35:16] Most likely you have input the wrong URL, forgotten to add a port, or have not set up workers
[19:35:16] Pool: 0 URL: stratum+tcp://pool.ipominer.com:3335 User: --------------------------
[19:35:16] Pool: 1 URL: stratum+tcp://pool.ipominer.com:3626 User: --------------------------
[19:35:16] Pool: 2 URL: stratum+tcp://pool.ipominer.com:3601 User: --------------------------
[19:35:16] Press any key to exit, or sgminer will try again in 15s.