I am trying to download a file from a url using curl but I am running into an error.

$ curl -3 -v "https://atl1mmsget.msg.eng.t-mobile.com/mms/wapenc?location=18188257544_14zbwk&rid=027"

* Adding handle: conn: 0x2140cd0
* Adding handle: send: 0
* Adding handle: recv: 0
* Curl_addHandleToPipeline: length: 1
* - Conn 0 (0x2140cd0) send_pipe: 1, recv_pipe: 0
* About to connect() to atl1mmsget.msg.eng.t-mobile.com port 443 (#0)
*   Trying 66.94.0.188...
* Connected to atl1mmsget.msg.eng.t-mobile.com (66.94.0.188) port 443 (#0)
* successfully set certificate verify locations:
*   CAfile: none
  CApath: /etc/ssl/certs
* SSLv3, TLS handshake, Client hello (1):
* SSLv3, TLS handshake, Server hello (2):
* SSLv3, TLS handshake, CERT (11):
* SSLv3, TLS handshake, Server finished (14):
* SSLv3, TLS handshake, Client key exchange (16):
* SSLv3, TLS change cipher, Client hello (1):
* SSLv3, TLS handshake, Finished (20):
* SSLv3, TLS change cipher, Client hello (1):
* SSLv3, TLS handshake, Finished (20):
* SSL connection using AES128-SHA
* Server certificate:
*    subject: C=US; ST=Washington; L=Bothell; O=T-Mobile USA, Inc.; CN=apgw.sipgeo.t-mobile.com
*    start date: 2013-05-21 21:02:44 GMT
*    expire date: 2014-05-22 08:35:43 GMT
*    subjectAltName: atl1mmsget.msg.eng.t-mobile.com matched
*    issuer: C=US; O=Entrust, Inc.; OU=www.entrust.net/rpa is incorporated by reference; OU=(c) 2009 Entrust, Inc.; CN=Entrust Certification Authority - L1C
*    SSL certificate verify ok.
> GET /mms/wapenc?location=18188257544_14zbwk&rid=027 HTTP/1.1
> User-Agent: curl/7.32.0
> Host: atl1mmsget.msg.eng.t-mobile.com
> Accept: */*
> 
* HTTP 1.0, assume close after body
< HTTP/1.0 501 Not Implemented
< Server: BigIP
* HTTP/1.0 connection set to keep alive!
< Connection: Keep-Alive
< Content-Length: 0
< 
* Connection #0 to host atl1mmsget.msg.eng.t-mobile.com left intact`

What does the 501 not implemented error mean? How can I get around this?