REGISTER getting 404 not found in OCCAS

I have 2 scenarios in which one works and one doesnt. We try to register a SIP phone with the domain and it is successful. If we try to register with an alias it is not. Here is the nslookup and the unsuccessful REGISTER. I see the following in RFC 3261 but dont really understand what it is saying and dont know if it is related. I pasted the following in this order. RFC quote, nslookup result, REGISTER followed by 404 in sip-messages.log. It shoulkd be noted that the REGISTRATION that works is with the canonical name rchtpocsipvip.vzbi.com.

The registrar extracts the address-of-record from the To headerfield of the request. If the address-of-record is not validfor the domain in the Request-URI, the registrar MUST send a404 (Not Found) response and skip the remaining steps. The URIMUST then be converted to a canonical form. To do that, allURI parameters MUST be removed (including the user-param), andany escaped characters MUST be converted to their unescapedform. The result serves as an index into the list of bindings.