Mac Mail - Outlook Exchange issues

commanderclif hello have you found a solution to this issue? I run into this once a year or every 6 months depending on email volumes when the mailbox size or mail count goes over a "certain" size. On Catalina, I did my usual archiving  and clean build and all 80,000 emails downloaded and it was working smoothly then it just stopped again. 

2. Tried Big Sur it does the same thing,

3. Got a brand new MacBook Pro out of a box  top end, 32 GB that's all we use ( not M1 yet) and rebuilt it and 4 days later same thing. As an aside: If you have a 30 Gig mailbox with a lot of items AppleMail takes days to get caught up and yes I don't downlead ANY attachments or store items on the server. Not sure why Outlook can download a 60Gb MB in less than a day and useable immediately where AppeMail is pretty useless until ALL of the old emails downloads. I think Outlook does pointers and only the new emails first.

Of course:

1. Rebuild mailbox gets all new mail

2. Open and closing the client does them same sometimes.

3. Deletion and sending new email still work normally.

Same issue everyone else sees "checking mail. No new mail"  when in fact there are many I see on webmail and Outlook. Or it does nothing no activty in activty montor or in mail client WIndows Activity

They have a strong dislike for Outlook but of course Outlook and EAS ALWAYS works. So they have to use Outlook while Apple addresses the issue.

Apple can you please see what's going on because something has changed. It is not end user error here for all of us.

Thanks,