Cannot connect to server using message server: ms://hostname:8101/P4

Hi Experts,

        We have installed PO 7.4 SR2 java stack only.  when i try to click ESR in  http://Hostname.FQDN.com:50000/dir/start/index.jsp  link after loading java am getting the error like  Cannot connect to server using message server: ms://hostname:8101/P4.

         When try to connect from remote system am this above error message. In PI installed local system am able to access this link successfully.

In my local system host directory i have added like this 10.xx.xx.xx     Hostname      Hostname.Domain_name.com. This also not resolved my issue.

     This is very Urgent... Please anyone guide me to resolve this issue...

Regards,

Vetri