Sending, receiving, and organizing email in Outlook on the web for business
Hi Hannah,
Since you're still able to receive emails from your coworker, it appears that email delivery within your organization is working.
If emails from external senders are not arriving and no bounce-back messages are being reported, there are a few things you can review first:
- Your Junk Email folder.
- Any Inbox Rules in Outlook (Settings > Mail > Rules) that might be moving, deleting, or redirecting incoming messages.
- Review the Blocked senders and domains list (Settings > Mail > Junk email) to see whether any expected senders or domains have been blocked.
If everything appears to be configured correctly and the affected senders or domains are not listed as blocked, I would recommend contacting your IT administrator. They may be able to run a Message Trace to determine whether messages from external senders are reaching your organization's mail system and what happened to those messages during processing.
If you are unsure who your IT administrator is, you can refer to this official Microsoft guide for assistance: How do I find my Microsoft 365 admin? - Microsoft Support.
I hope this information is helpful. Feel free to update the thread with your findings, and I'll be glad to assist further.