Ben, add the details below;

If you encounter Linksys error code 2123, you are facing an Unexpected Error with the Linksys router. To solve the problem, simply reset and reconfigure your router. To reset the Linksys router, go to the diagnostics settings of the router, then click the Reset link. (https://www.paessler.com/help/linksys-errors)

For specific instructions for resetting the mesh network see https://support.linksys.com/kb/article/274-en/

Once in awhile, for no know reason, the WiFi network will go brain dead and unresponsive to administrative work. At this point I have found no information on why this occurs, only that the solution is to reset the entire network.

Notes on Resetting The Mesh Network
09.13.24

Model MX4200
_VelopSetupC76
Password: v3ge3nkqi2
Recovery key: 07801
SN: 38U10M34B06281
MAC: e8:9f:80:eb:9c:76

Model MX4200
_VelopSetup540
Password: zmnyyizs2m
Recovery key: 18533
SN: 38U10M39A23896
MAC: e8:9f:80:43:55:40

Model MX4200
_VelopSetup504
Password: cpzu2yd028
Recovery key: 25033
SN: 38U10M39A23884
MAC: e8:9f:80:43:55:04