Outlook won’t open after closing

I have a user that when he closes outlook, it will not reopen unless the user restarts the computer. I checked task manager when reopening outlook, while outlook seems to start and show up in the details list, it does not open.
If the user restarts outlook then it works without issue until he either closes outlook or tries to reopen an email. Then the user is unable to open either.
We are using O365 with an E3 subscription and Windows 10