My mail apple account on my ipad does not work in cellular mode but does when I am on any wifi, home or public. My iPhone works well on both? I just got a new ipad and the issue transferred from my old ipad. I am running 5th generation iPad Pro and current IOS 15.2.
iPad Pro, iPadOS 15
Go to Settings. Click on Mail. Click on the button-turns green-for cellular use in Mail settings.
Go to Settings. Click on Mail. Click on the button-turns green-for cellular use in Mail settings.
Presumably you have a WiFi+Cellular model of iPad - and that the iPad itself has an active Cellular Service plan?
If you can send and receive email when using WiFi, but not Cellular, check that you have enabled Mail over Mobile Data in iPad settings:
Mail does not work on cellular but does on wifi
