I'm seeing the same issue here. I have my root domain name set in the only option for XMPP but when i try and connect the prosody_debug log is showing
Nov 08 22:23:31 socket debug server.lua: accepted new client connection from 127.0.0.1:43055 to 5347
Nov 08 22:23:31 jcpaf1010 info Incoming Jabber component connection
Nov 08 22:23:31 mod_component info Disconnecting component, is: asterisk.domainname.com does not match any configured external components
Nov 08 22:23:31 jcpaf1010 info component disconnected: nil (false)
Nov 08 22:23:31 socket debug server.lua: closed client handler and removed socket from list