Hello, thank you for reaching out to Microsoft Q&A.
- Are you able to send emails?
- Did you check your Junk or SPAM email folders to see if all of your incoming emails are forwarded to that address?
What is the exact error message the sender receives when they email you?
Send a test email from another one of your accounts to the affected email address. Check whether you receive any bounce-back (non-delivery) error messages or see if the email gets stuck in the Outbox. If you receive an error, please share the complete error message here.
If the email was sent successfully, please check your email forwarding rules and blocked senders list, and verify whether the messages were routed to another folder, such as Junk or Spam.
Open any web browser and sign in with your Microsoft account on the link below.
Email forwarding rules: https://outlook.live.com/mail/0/options/mail/forwarding
(Click Do not forward if your emails are being forwarded to another e-mail address)
Additionally, ensure you have sufficient mailbox storage to send and receive emails.
To check that, go to Outlook email settings > Accounts > Storage.
To check your Blocked Sender's lists or Rules,
Go to Outlook email settings > Mail > Junk Email > blocked sender's lists.
For Rules, select Mail > Rules.