Before the messages app on my iPod 5 with iOS 9 was working fine, but yesterday I was signed out for some reason. When I tried to sign back in, it said that I needed to verify an email address and redirected me to the apple id site. I already had a verified email address, but it still would't let me sign in. I've tried re-verifying my email and verifying a new email address but I still get the same pop-up message. How can I sign in?
Problem solved. I just went to the apple id site and changed my apple id email to one that had been previously verified. Works now.