Follow the steps below to fix the issue:
1. Go into the hub’s control menu.
2. Select Report Config.
3. Check the timeline, and you will see the following system updates: If arc":[{"arcId":"'} appears, it indicates that the hub is missing the ARC ID, even though it is displayed on the dashboard.
Example:
4. Go back to the hub’s control menu and select Update Config.
5. Allow a few minutes for processing, then check the timeline. When you see {"arc":[{"arcId":"4000439"," it means the hub has successfully received the ARC ID.
Example:
6. The hub will now make successful calls, and the display will change back to ‘press and hold to call’.