For a few days now I cant connect to opticraft. The problem is really specific , when I try to log in I connect but I seem to fall down and the terrain is not loaded and after few seconds I disconnect. However I can play fine in single player or in other online servers so the problem is only for opticraft... Around that time I was installing some ASP.net stuff for school and I suspect that they messed up my connection , however after I deleted them I still couldn't connect. I scaned the pc for viruses and I found lots of them but this didnt help too. Finally I reinstalled the whole pc BUT this did not help also ...
I am suspecting that some program or virus or whatever is occupying the same port that opticraft is using and that is why I cant connect there but I can everywhere else. Does anyone know any details about opticraft , what port does it use and any other specifics that can help.(so I can see if anything is using the same port) Or if you have any other ideas I am open to suggestions :/

P.s  + other computers can connect to the server from my internet connection so I dont think the problem is with the internet

failed to connect to the server failed to login invalid session try restarting..  so every time I try to connect to the server this message appears , I hare restarted 100 times and downloaded different lunches but the same message apears ... Any ideas ?