Call between two Kphone (SIP phone in SUSE) - bridge prblem?

Hello,
I need some help to understand this.
Two Khone used as SIP phones are regsitered (phone 200 and 202)
200 calls 202.
202 is ringing and the call is answered.
Than it seems to hang.

CLI> Aug 12 09:45:35 NOTICE[7143]: chan_sip.c:9530 handle_request_register: Registration from ‘“OldLaptop” sip:202@sip.site2.’ failed for ‘192.168.2.198’
– Executing Dial(“SIP/200-859d”, “SIP/202”) in new stack
– Called 202
– SIP/202-80f9 is ringing
– SIP/202-80f9 answered SIP/200-859d
– Attempting native bridge of SIP/200-859d and SIP/202-80f9
== Spawn extension (internal, 202, 1) exited non-zero on ‘SIP/200-859d’

Here the SIP.conf

[200]
username = 200
context = internal
callerid = “Jane Smith” <200>
secret = 123456
host = dynamic
type = friend
login = 200

[202]
username = 202
secret = 123456
host = dynamic
context = internal
login = 202
type = friend

Extensions.conf

[internal]
exten => 200,1,Dial(SIP/200)
exten => 201,1,Dial(SIP/201)
exten => 202,1,Dial(SIP/202)

Any idea what is wrong?
thanks in advance for the help
Eric