I had to set up a new email for a person yesterday and they use outlook 365 and we had a heck of a time, we were able to set it up on a phone and their laptop that has office 2019 on it. However, their connected outlook 365 kept on failing. Now there are like 20+ of these ghost accounts on the left sidebar and no way to get rid of them because they don't show in managed accounts or in mail accounts. There is no right-click option to remove them either. We tried getting rid of their OST files but when we restarted the PC and relaunched they all came back the ost files.