Outlook MacOS - Downloading Attachments from the Server (Nonfunctional)

Good day,

I'm reaching out for help with an ongoing issue I'm experiencing with my email accounts on Outlook. Two days ago, all of my accounts suddenly stopped being able to send or receive emails. This issue appeared out of nowhere and has since become a constant problem.

I've tried removing and re-adding the accounts, but this hasn't resolved the issue. Now, my emails won't fully load, and I consistently see a "Downloading Attachments from Server..." message in the reading pane that never progresses. Additionally, the email previews are not showing up.
I have also deleted Outlook entirely and re-installed it but that also did not work.

Interestingly, these email accounts work perfectly on other mail clients like Mail on Mac and RoundCube. In Outlook, however, emails are not sent or received, and test emails remain stuck in the Outbox.

Please note, these are IMAP email accounts.

I have already reached out to the domain hosting providers, but they were unable to assist. If anyone has encountered a similar issue or has any suggestions on how to resolve it, your advice would be greatly appreciated.

Thank you in advance for your help.

Also, I tried to attach a screenshot, but it seems as if everything is broken because the file fails to upload.

Kind regards,

D

System Information:

Macbook Air M1

MacOS Sonoma 14.4.1
Office 365
Outlook Downloaded from App Store