Call Connecting Issue

Dear All,
i’m getting following error on Asterisk consloe and call is not connecting.

[Jan 23 09:28:11] WARNING[527]: chan_sip.c:17893 handle_response_invite:

Re-invite to non-existing call leg on other UA. SIP dialog

'6fd6d1cd148e44755c74a6b52070f42a@sip.skype.com’. Giving up.
– SIP/skype_connect-00000a0a is circuit-busy
== Everyone is busy/congested at this time (1:0/1/0)

Please advise.

SIP trace needed, plus proper identification of the remote system type.