Hi @Will West ,
Welcome to our forum!
According to your description, i notice that you encounter a issue with alias. Please note:
Existing Hotmail, Live, Outlook.com, and MSN addresses can't be added as aliases, and you can't add an alias that is already associated with another Microsoft account.

More information: Add or remove an email alias in Outlook.com.
If the above doesn't help, please kindly understand that the Outlook tag here we mainly focus on general issues about Outlook desktop client. It's suggested that you could post your case in dedicated forum for Outlook.com for more professional advice.
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