I have 2 MAX HD2 units both running firmware v6.3.2.
One of these units is deployed on a remote asset, using two cellular connections and a WAN connection. Recently we lost contact with the remote system and had to do a site visit to debug the issue. I found that the LAN side of the router was operational, systems connected with their proper IPs and could access all services from the systems on the LAN. When logging into the router admin I found that the WAN connection area was just a spinning box, similar to when the unit first boots, like the following picture:
Rebooting the unit fixed the problem and I have enabled the watchdog and set the unit to reboot daily so that if the issue occurs again we are hopefully only locked out of the system for a maximum of 24 hours.
This issue occured on my second MAX HD2 unit in the office after a quick power loss, I have been trying to reproduce and have been unsuccessful. My best guess is that some exception occurred on the starting of one of the WAN connections which hung the process.
The issue seems similar to the one found here: