Sony dcr-dvd408 can't open the access door to get the tape. I hear cliking but it won't open

This can be due to failure of the loading motor mechanism . Since you are hearing the clicking sound , it is possible that the motor is working to the command from the processor but there is failure in the mechanical drive., This can be due to pulley slipping , gear failure or belt failure.
Unless the camera is opened to remove the covers and get access to the mechanism , the exact fault cannot be confirmed.