Minecraft Hamachi Server

I am on a Macbook Air, not the newest version, and I often play minecraft with my friends on their servers. Recently I have not been able to connect to their servers. Sometimes I am on the server and it times out, and then I cannot get back on. I have restarted my minecraft, hamachi, wifi, and even my computer but it is very un-realiable when i can get on and stay on. I would like to play with my friends!!!!!! please help!