I guess, Preferred server access setting messed up.
1. Are you try to access host server?(yes/no)
if yes--> please check host server is enabled Telnet access or not.
if no --> please make your Cache as preferred server
Click Cache -> Preferred Server -> This Server
And click terminal, Once you click on terminal, Cache automatically starts by itself and you will get access to Management Portal, Studio.
Still you find some issue to access cache, please Check cconsole.log,