my account has this weird address outlook_(a few numbers)@outlook.com.

Hi Val Moore

Thank you for your reply.

If you have made @outlook.com is it the primary alias and your non-Microsoft email is the secondary alias. Then you need to wait at least 48 hours for the alias to take effect. (I apologize for not informing you in time in my last reply)

Secondly you should be sending your email from Outlook Web. I suggest you log into your primary alias @outlook.com in Outlook Web and set the default sender address to your non-Microsoft email address under Settings - Mailboxes - Forwarding and IMAP, Email Aliases.

After waiting for 2-3 days you should be able to send emails, what I want to add to you is that you can send emails using non-Microsoft mailboxes in Outlook Web, but the emails received by the recipients will have the words “Outlook sends on behalf of the recipient” and the recipients who want to reply to the emails from your non-Microsoft mailboxes will need to go to your non-Microsoft mailboxes to view them, you can't view their reply emails in Outlook Web. You will not be able to view their reply emails in Outlook Web.

Thank you for your patience and support! 

I wish you all the best

Linda.W-MSFT | Microsoft Community Support Specialist

Dear Val Moore

Thank you for posting to Microsoft Community

I understand that your account is showing a strange address and you are unable to receive emails. Don't worry, I will help you in any way I can.

When a user registers a non-Microsoft domain account (e.g. @Gmail.com) as a Microsoft account, the system automatically generates the relevant email address as the default email address, i.e. [outlook_[long string of letters and numbers]@outlook.com]. As this is a temporarily generated email address. It is only used as a username and is not a valid mailbox domain and belongs to two different accounts than the non-Microsoft domain mailboxes, so it cannot receive emails.

You can visit Microsoft account | Sign In or Create Your Account Today – Microsoft, log in to your non-Microsoft mailbox, and click [Your Info]-[Account Info]-[Edit Account Info] You can add an @outlook.com alias to your account in this screen, and then log in to the @outlook.com alias to send/receive/download emails from the non-Microsoft domain.

For more information about adding an alias, see: Add or remove an email alias in Outlook.com - Microsoft Support

I hope you find this information helpful. If you have any questions, please let me know and I'll be happy to help!

Have a nice day.

Best Regards,

Linda.W-MSFT | Microsoft Community Support Specialist

Hi NadineAM632

Thank you for your reply.

You're welcome. It's an honor to help you.

I wish you all the best

Linda.W-MSFT | Microsoft Community Support Specialist

Thank you so much! Really appreciate all your help!

Hi Linda

Thank you so much! I have now logged in using the @outlook.com address. I tried to add the non-Microsoft address as a alias but it says it already exists and does display under my name as a alias but when I try to send emails I get a bounce back saying I don't have permission to send from this account.

Thanks