Cannot delete draft messages in Apple Mail (12.7.2 Monterey)

Well, it looks like the problem is solved. I rebooted my router and cable modem.

But it's strange. Last night I had rebooted both my cable modem and router yet that didn't resolve the problem.

After mail started being responsive again, I did enter the IP addresses you suggested just to try things out. But I saw no appreciable difference in performance. Thus I believe there was something wrong with my home network. But I cannot figure out why the reboots last night did not resolve the performance problem.

Thanks much for your input @BDAqua.....

I still have the problem of 55 Draft messages when there should only be 8. But I believe that this is another problem that is unrelated to the performance issue (Mail not loading messages). I filed a bug using Apple's Feedback Assistant.

Last night's rebooting into Safe Mode should have cleared caches according to @BDAqua, correct? So there must be some other problem that I have not yet identified.

Well, I did everything you instructed. Now it seems that the Mail process is getting in the "stuck" state again. And message bodies are displaying slowly again; I have to wait a few minutes at least to see the message.

I think I'm going to just delete the mail account and re-add it. All of my content is on the server so it should not be a problem other than taking a long time to download all the contents.

I'll report back when I've done that....

Microsoft Outlook (Exchange account)....

I have no choice; it's my university alum email service; they chose Microsoft; what can I say....?

I thought it might be Microsoft. Today, as part of my tests, I forwarded several emails to a gmail account I have. I could open the message bodies immediately in Apple Mail.

I can't say that test was conclusive as I have basically no emails in that gmail account (I don't use gmail).

I'm eager to hear any suggestions regarding problems with Outlook mail servers (Exchange).

This article:

https://support.microsoft.com/en-us/office/outlook-is-running-slow-115e5ce0-5823-4df8-b129-33513963e611?ui=en-us&rs=en-us&ad=us#ID0EACAAA=Office_2011

Discusses problems for large number of messages in the inbox. My inbox has only 132 messages.

I have many, many folders in this email account. I don't seem to be having much of a problem loading messages from folders (not the inbox).

I've had many more messages in my inbox in the past. But I never experienced this problem until I upgraded to 12.7.1 and then 12.7.2.

One additional piece of information.

I do not experience any of these problems when using the web interface to outlook.office.com/mail.

So I'm inclined to believe the problem is with Apple Mail. And, as I said previously, I've been using this configuration (Mail accessing the same Exchange account) for several years without ever this problem. The problem only started after the Monterey upgrade to 12.7.1. and 12.7.2.

Hi, thanks for the reply.

I have the box ticked that says "Store draft messages on the server"

I will do the Safe Mode boot now....

Microsoft O365 cloud-based email service.... (Exchange server)

Do I need to do anything to mark this issue "closed" or "resolved"?

OK, thanks much @BDAqua...!

Onwards and upwards...!