Apple Mail connection error question

I am a long time Outlook user (my work uses Exchange), but I am giving the more native apps a shot, including Mac Mail to access the Exchange server. It seems to usually work well, but I am sporadically getting this message:

The operation couldn’t be completed. (MCMailErrorDomain error 1030.)

The thing is - nothing SEEMS like it has gone wrong at the time I get the error message. When I clear the message, things seem to be working ok. I haven’t noticed any message fail to receive or send, or delete, or move to a folder. (Of course I could be missing it).

How do I troubleshoot this? Is it possible there is just a momentary drop in the connection with my Exchange server and this message flashes up on the screen. I am nervous trusting the Mac Mail client when I get these messages (as I don’t get anything like that with Outlook - other than being occasionally notified that Outlook has lost connection).

Any help or guidance would be greatly appreciated!!

I’ve had this happen in the past, what solved it for me at the time was re-adding my password in the SMTP server settings.