Activation denied because server is Unavailable???

After using my 32GB ipad for a few years, I was suddenly asked to activate it when I turned it on as if I had never used it before. The first two times this occurred, I simply entered my apple id and password and the home screen popped up like usual. This time however, when the activation screen appears and I enter the apple id and password, I get the message that "Your iPad could not be activated because the activation server is temporarily unavailable." I tried going through ITunes, but after typing in my apple id and password the message that there is "an unknown error (0xE8000013) and it can't be activated" follows.