Hello @jtrexel!
My apologies that it is not letting you create a new Access ID for your wireless number! You came to the right place and I will be happy to assist!
If you are getting the error message that the number is already associated with another Access ID, you will just want to de-link that account from your wireless number. Check out our support article Manage online access for your ID or accounts for specific instructions!
After doing this, you should be able to Create your AT&T Access ID. Just keep us updated and let us know how that goes! Have a great day!
Tim, AT&T Community Specialist