I think they are doing some kind of wallets maintenance - so I read in their news page.

Aug 2nd
From: Richie

Wallets infrastructure under mandatory Azure maintenance
As we alluded to last night, Azure has a maintenance window starting at 20:00 PDT that will affect all our wallet servers. We expect wallet servers to be up and down most of the night, including the bitcoin wallets. We will try to minimize downtime, but it will take some time for us to bring things back up clean and audited.