I am working now, but mention this because it cost me a considerable amount of time. It started when I tried to tell Photos app to email a photo for me, and saw it was failing because it was using my gmail address. Not sure how this happened but I simply removed my gmail from the iPhone and then whenever I opened Mail app it asked for account, so I answered "iCloud" and then entered my email(AppleID) and iCloud email password. The phone would go into "Verifying" and then return for asking for the appleID/password at the same page. No error was shown, it would just return after "Verifying". The same would happen if I went to "Settings/Mail/Accounts/Add Account/" as the account was already there and my iCloud disk could be seen.
To get Mail working again all I had to do was
"Settings/(AppleID with my picture)/iCloud/iCloud Mail/" and flip the first line with "iCloud Mail" to enabled.
(Below this line it now says "Send and receive email using your @icloud.com email address")
Perhaps 99% of you know this, but I post this for the 1% (like me) who is not very knowledgeable of how to use my iPhone.
Since the user intention seems clear, I think the IOS 15 should be smart enough to enable the iCloud Mail when the user tries to add the (pre-existing) iCloud account from the Mail app, but at least we are forewarned.
To get Mail working again all I had to do was
"Settings/(AppleID with my picture)/iCloud/iCloud Mail/" and flip the first line with "iCloud Mail" to enabled.
(Below this line it now says "Send and receive email using your @icloud.com email address")
Perhaps 99% of you know this, but I post this for the 1% (like me) who is not very knowledgeable of how to use my iPhone.
Since the user intention seems clear, I think the IOS 15 should be smart enough to enable the iCloud Mail when the user tries to add the (pre-existing) iCloud account from the Mail app, but at least we are forewarned.