I ran into an issue where two of our C20's would not connect and could not be reached. These devices are down stream from a Meraki which was connected and remote capabilities to it were operational. The C20 had the appropriate IP, subnet, and GW. The local hands on support also verified that DHCP was selected. They rebooted the C20 and after it completely powered up it still would not connect even to the local Meraki device. The Meraki would see if disconnect on reboot and when it came back up would green up and pull the MAC and its IP.
In order to fix it I was able to change the IP scope that the Meraki was handing out. After another reboot of the C20 they reached out and pull an IP from the new scope and were then able to connect and register.
This has happened before with another tech and they fixed it in basically the same way. the trigger for them was a circuit cut to the site. Which is what happened here as well.
We are in the fortunate situation where we have the capability to swap IP scopes but I am unsure of the root cause of this issue.
Both of the C20's are on TC7.3.20