I have configured the native mail app for office 365 and mail works fine on Wifi but cannot get mail on cellular network.
Strangely it's fine using the MS Outlook App and I can browse to Office 365 OWA OK
So, the problem is isolated to the native IOS Mail app on Vodafones mobile network (either 4g or 3g... doesn't matter)
Server = outlook.office365.com and Exchange provider
Can anyone help???
Vodfone network settings look OK too
Does the info on this page help at all?