Cannot Send Mail: The sender address was invalid
I bought the latest brand new iPad Pro and restored the backup. All email settings are the same as on the previous iPad. However I constantly get an error when trying to send mail: Cannot Send Mail The sender address was invalid.
I checked iPhone settings and set this account up EXACTLY the same as on the iPhone. Cannot Send Mail The sender address was invalid.
I deleted the account and set it up again fresh. Cannot Send Mail The sender address was invalid.
I searched for help online and followed instructions. Cannot Send Mail The sender address was invalid.
For a brand new iPad Pro, this is a disappointing experience and huge time waster. Any help would be appreciated.
iPad Pro (6th generation)