Ejabberd not allowing registration from client

I've got an ejabber cluster setup. When trying to register a user with a client (say Adium) I'm getting a 503: Service Unavailable error. I'm running ejabberd 2.1.x

The log shows this:

E(<0.389.0>:ejabberd_hooks:335) : {{case_clause,
                                   {value,{access,register,[{allow,all}]}}},
                                  [{gen_mod,get_opt,3},
                                   {mod_register,try_register,5},
                                   {mod_register,process_iq,4},
                                   {mod_register,
                                    unauthenticated_iq_register,4},
                                   {ejabberd_hooks,run_fold1,4},
                                   {ejabberd_c2s,
                                    process_unauthenticated_stanza,2},
                                   {ejabberd_c2s,wait_for_feature_request,2},
                                   {p1_fsm,handle_msg,10}]}
running hook: {c2s_unauthenticated_iq,
                 ["domain.com",
                  {iq,"purple111a7fa3",set,"jabber:iq:register",[],
                      {xmlelement,"query",
                          [{"xmlns","jabber:iq:register"}],
                          [{xmlelement,"username",[],[{xmlcdata,<<"user">>}]},
                           {xmlelement,"password",[],
                               [{xmlcdata,<<"psd">>}]}]}},
                  {{my local ip},56632}]}

domain.com is my domain, user is the username, pass is the password and my local IP is the local IP of the machine I'm on.

Any ideas?