iOS 10 mail app not functioning properly
I have a 6s and just downloaded iOS 10 today. My mail app inbox keeps loading the same 4 previously deleted emails and says it was last synced 8.28.2016. Then it says "checking for mail, cannot get mail, the connection to the server failed." I click ok to exit the pop up box, go click on mailboxes, then all mailboxes and it brings me to my current inbox. What does this mean and how can i fix it, so i don't have to keep going out and clicking on all mailboxes everytime? I've tried restarting my phone. Everything else is functioning properly. Thanks!
iPhone 6s, iOS 10