If you are not receiving emails from a specific person or company, they may have been accidentally added to your blocked senders list. Instructions for New Outlook/Outlook.com:
Elias stared at the glowing ticket on his screen. The subject line was written in all-caps, the universal sign of professional panic: unblock outlook
The Exchange server had seen a single email trying to consume a quarter of its bandwidth and had simply said, "No." If you are not receiving emails from a
Elias took a sip of his cold coffee. He opened the PowerShell terminal. He was going to have to perform surgery on the live mail queue. He opened the PowerShell terminal
Sending a large volume of emails, especially to non-existent addresses.
He executed the command. He intercepted the email in the pipeline, deleting it from the server’s outbox before it could choke the network, but—crucially—preventing a "Failure Notification" from hitting Sterling's inbox.