This problmes caused by your client is not updated or the server is not the corecly serials whit your main.exe!
Try to hex your main.exe and find the serials if the serials it`s same whit your server it`s ok ... now the problems have in server ! Try to make this and share more info !
Good Luck !
Here
i edit to with HexEdit
OK i already fix it
Client is not updated
thanks for reply!