[Serusers] [Windows Messenger SIP 5.1] Problem with "Send an instant message"

[Malik NakaMura]

Hi,

My configuration :

- Windows Messenger 5.1 SIP installed on 2 PCs (Windows XP)
- Ser v0.9.6 installed on Mandrake 10.1

The problem is that I have this error : "The following message could not be 
delivered to all recipients : my message" when I send an instant message, 
but the voice call works very well... with Ethereal I see that the instant 
message receiver send these requests to Ser :
- Trying
- OK
- BYE

why does the receiver send BYE whereas the transaction is not finished ?

my traces from ethereal :

from Ser(192.168.10.137) to Receiver(192.168.10.127) :

	INVITE sip:192.168.10.127:10835 SIP/2.0

from Receiver(192.168.10.127) to Ser(192.168.10.137) :

	SIP/2.0 100 Trying
	SIP/2.0 200 OK
	BYE sip:192.168.10.137;ftag=6a036c30432a4e0dab11dda94916e9ea;lr=on SIP/2.0

from Ser(192.168.10.137) to Receiver(192.168.10.127) :

	ACK sip:192.168.10.127:10835 SIP/2.0
	MESSAGE sip:192.168.10.127:10835 SIP/2.0
	SIP/2.0 200 OK

from Receiver(192.168.10.127) to Ser(192.168.10.137) :

	SIP/2.0 481 Call Leg/Transaction Does Not Exist


thanks in advance,

Best regards,

Malik