I have 3 pop3 accounts set up under the Mail App. One of them behaves like Outlook 2016 pop accounts. It does not remove a message from my cox.net server when I delete a message in the app. The other 2 remove a message from the server when I delete it in the app. I have checked the settings for these two apps against the settings of the one that behaves as I think it should. All app settings are identical as are the cox webmail settings for each account.

Can someone please help me getting the two misbehaving apps to not delete the messages from the server? If I have to delete the app and reinstall it that is fine with me but I haven't a clue as to how to do it.

Thank you very much.