Hi theBee,

To help you further with this issue we would like to have more information regarding it

1.  What is the Operating System you use?

2.  What is the version of MSN Software?

3.  Please provide the email address you want to associate with MSN premium account?

Things to try:

If you are trying to associate a different email address domain with MSN it is not possible, however you can associate email address with the live id domains (@hotmail.com, @live.com).

Please follow the below given steps to associate your email account with the live id domains (@hotmail.com, @live.com).

1. Sign into your MSN email account ( Primary email account)
2. Click on Help & Settings
3. In the left pane click on ‘Show all settings’
4. Under Account & billing click on Add member account
5. If your already have a MSN or Hotmail email address select the option 2 and enter your email address and the password
6. Click Continue
7. Next screen Review and sign agreements type in your mail in the box and click on ‘Accept’ 

Please reply back for further assistance

Thanks!