Error in connecting to server using SSH

Hi,
I am in a situation that stopped the flow of working and it is due to the sharing between the systems on the LAN with an operating system as Ubuntu. I have tried using SSH by opening open ssh with the connection made to the server and then can browse some files from S of A.
Now I am unable to connect through A to S as the connection request timed out and disabled the firewall located on A. I am being worked on this from the past month in which no solution found from that time and no solution is available in any forum or blogs. Actually I need the solution to using like Ubuntu, Dropbox so any solution for you will be a great help for me.
