Ghazala,

 

    The firewall is OK , the client could cummunicate with the server .

    'This account is using. Please try again' means that , a use want to get in a room , but the server reject it while it not leave in last session .

    One account could get in same room at the same time , may be you open 2 windows , or please wait for 1 minitue and retry

 

Regards , Terry .