While I haven’t been able to find any official announcement, it appears as though the Starz and Encore TV networks have been experiencing some technical difficulties the last couple of days. A little research online will show a few support forum posts of people with the same issues. It also appears that it is nationwide, not just regional.

Some of the channels may not work, others will see a message about technical difficulties. So far I have found reports for At&t U-Verse, Verizon FIOS, Dish Network, and DirecTV.

DSLReports
SatelliteGuys
At&t Forums