Hi Reza,
The link is incorrect:
http://sapqxa.vestas.net:50200/text/logon?version=1.2
50200 is the HTTP port of the server node, not the message server.
To find the J2EE message server port, check the dev_ms file in /usr/sap/<SID>/SCS<nr>/work and for the
ABAP server , check the /usr/sap/<SID>/DV.../work/dev_ms file.
For example in the above server, 8177 is the message server port.
Regards,
Hemanth