Unable to login to iCloud on iPhone 6s
I have an iPhone 6s version 10.1.1. A few weeks ago my phone shut off on its own and turned back on. When it came back on, I noticed my contacts were missing. Then I noticed my work email (exchange sync account) was missing. I went into settings and selected iCloud and signed in and it shows at the top it's verifying, but it stays on the sign in screen.
I can't find anything online to help with this. Please help! I need my calendar back and my email and the ability to set reminders.