By default, calls go to voicemail when a line is busy. As an administrator, you can turn off this feature, so a caller will hear the phone ring without an option to leave a message. After it has been turned off, you can turn it back on.
Note: We recommend you don’t turn off this feature because callers can't leave a message.
To have calls go to voicemail when a phone is not answered, this feature needs to be turned on.