E mails not arriving on my I pad

Delete the Mail app then reinstall.

Same here last week, had to change password with Outlook settings.

This happens to me occasionally and it asks me to re-enter my password.

This happened to me at the weekend too. The emails on my Mac seemed so be opened in a different way and then the ones that I’d just sent completely vanished. Quite mystified. Turned everything off, had lunch, and they all reappeared later. Very odd. I also had to reenter my Microsoft password.

I had this at the weekend and eventually, I had to re enter my password in the Outlook settings. It worked!

Contact Apple Support.