Double check the settings in your Outlook account to make sure that you have specified to receive emails from the sender. Check to see if any specific domains, addresses or people have been blocked.

Check your Spam and Junk folders to see if the specified emails were sent to them instead of your inbox. Whitelist the sender if necessary.

It’s possible that your email provider has automatically blocked the sender’s domain. Login to the email provider’s portal and unblock emails from the sender.

Check the settings of your antivirus software to make sure that emails from the sender are allowed through. Allow emails from the sender if necessary.