Intelli J connection error

I have installed plugin for cuba in intelli J idea, even after this there was a problem with connecting the IDE with the . Unable to connect to the IDE. Check if the IDE is running and CUBA Plugin is installed. is the error I am getting even though the plugin is already installed.

Which version of CUBA Studio and IntelliJ IDEA do you use?
Have you restarted the IDE after the plugin installation?
Note, the plugin uses port 48561 and it should not be busy at the moment of IDE starting.