Unfortunately we were hit by a DDoS this evening and our "Auto-DDoS-Mititgation-Script" got stuck and did not reenable Stratum, I've fixed this now and will add a second Stratum this evening (EU based, as I had some requests from there) which should be used as "Failover-Stratum" in future. CGminer will do this automatically for you if you omit two stratum urls, I'll explain this later.