old Apple ID verification keeps popping up
I changed my apple ID over a year ago and every once in a while a message would pop up saying: "Apple ID Verification: Enter the password for 'old email address' in Settings." But now with the IOS 10 update it is popping up every 15 seconds (yes, I timed it) and is extremely annoying. My phone is logged into my current apple ID and I have no issues with that, but this message is just annoying so, how do I get this message to stop popping up??
iPhone 6, iOS 10.0.1