Sometimes, after reading and then closing an email in Outlook (365) and returning to the inbox, I press the delete key to delete the email just read, and nothing happens. Then, I click on the Home tab and the Delete icon there - and nothing happens. Eventually, function is restored. But why such delays? Is there a limit on the number of messages that Outlook can handle and still function well? I do have lots of (imap) accounts and far too many emails, but Outlook has never had issue with this, before...