Hi @MW ,
Welcome to our forum!
What's your account?
Does this issue occur in Outlook desktop client?
If so, in order to further confirm if the issue is related to Outlook desktop client, please log in to web mail to check if you can receive the emails.
If everything is Ok on your web mail, please refer to the following article and try the steps mentioned in it to troubleshooting: I can't send or receive messages in Outlook.
Hope to help you!
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