When a user attempts to use the Click-to-Dial feature within the RingCentral for Google, an error message appears stating "You are currently in another call. Please end the call before starting a new one."
In most cases, this is due to the user being logged into another computer at the same time. It is also possible that another user on the system is logged in that user’s Google app due to using the wrong login credentials (usually the wrong Phone number).
Log completely out of any other computers and log into only one PC at a time. If multiple users on the system are logging into the same Google app, make sure their process is to login using their individual Phone number instead of the main company number plus their extension and password.