If the gripper is not communicating or is working intermittently, this is probably related to the cable
Troubleshooting
The first step will be to clean the contacts between the gripper and its coupling with rubbing alcohol and a gentle cloth.
If the connection is still unstable, Wiggling the cable changes the state of the status LED to red or off, indicating that some wires in the cable are broken.
If possible, try a different coupling/cable.
This troubleshooting step works with the standard RS485 connection, the UR wrist connection or with the Robotiq Wrist Camera connection.
Solution
Replacing the cable will usually solve the issue.
As this issue is usually caused by a stress on the cable, it is also recommended to review the cable management of the gripper for any enhancement of the reliability.
In order to get a replacement cable, contact the Robotiq support team (support@robotiq.com) and provide the necessary information. Since there are a few versions of this cable, a picture of the faulty cable will help the team determine what you need.