Sending, receiving, and organizing email in Outlook.com
Dear Jane Holehouse,
Welcome to Microsoft Community.
I understand that when you receive the email you get a bounce back indicating that it could not be sent.
This may have something to do with the rules, so please go to https://outlook.live.com and click on the gear icon in the upper right corner that
find “Mail”, check “Rules”, “Junk mail”, “Forwarding” to see if there are any unfamiliar rules, safe senders, or auto-forwarding turned on, etc.
Remove them and your account will be back to normal.
If these rules were not set by you, then your account may have been hacked at some point.
You can read the link below to strengthen the security of your account.
How to help keep your Microsoft account safe and secure - Microsoft Support
Feel free to post back if you need further assistance.
Best Regards,
Jason.YA - MSFT | Microsoft Community Support Specialist