Email not working after upgrading to IOS 10

I am having the exact same issues. I have changed (exchanged) my iPhone 7, replaced my sim, wiped my phone several time reset network settings, deleted and reinstalled the exchange account.

Nothing works. I am crippled!

Use the Apple configuration tool,

insert open part of server certificate

Create profile with Mail credentials and Certificate.

Send via Mail or put on web space the user can acces. User importes Profile, that's it

I Have same issue with iPhone 6s and 10.1.1 iOS. Frustrating!!!

We've just had this problem with one of our colleagues and I remembered that there's a mobile device limit associated with Exchange. It only lets you have a maximum of 10 "devices" but it seemingly logs a new device each time you upgrade the OS.

To solve this problem, we had to log in to Outlook Web Access (we connect using the Exchange's IP Address/OWA - eg "62.62.162.62/owa" but your setup may be different!), then go to Options > See All Options and then select "Phone" in the left had tool bar.

From here, you'll hopefully find that you've reached the maximum number of devices and will need to delete some of the older ones in order to connect successfully.

We deleted 3 or 4 of the older ones and everything worked fine... you'll probably find you need to do this again in a couple of years (or just ditch MS Exchange!).

Hope this helps.

All you need to do is enable "cellular" in settings for Mail.

I do not see any place in mail set up to turn on cellular. iPhone 5S

i have 10.2.1 and outlook wont connect, keeps saying cant connect to server. I have tried deleting it and adding back, then it works a bit then stops again. its ridiculous.

GO to setting. Click n Cellular. Scroll done to see the apps. Find mail and make sure it's on