error messages about 20 times a day

error messages about 20 times a day

I'm getting error messages saying that my account won't connect or I'm getting a "mailbox locked" message.  However, when I shut my outlook down and reopen it, it then works.  For my iphone, I have to reconnect it, then it works. Yet, I'll get the message again in 10 minutes.  I have attached some screenshots.

What do I need to do to fix this?