I've had a 3-node Deco XE5300 set for about a year, and it's worked fine until yesterday.  In the middle of the day my Internet went out -- i.e. the wifi network was still up, but I no longer had Internet access.

My Internet service is through Xfinity, and I have a Netgear CM1000 cable modem.  My cable connection is working fine -- if I connect a computer directly to the modem, I do have Internet.  In addition, I went out and bought a new wifi router (a TP-Link Archer AX20), and that also works fine when connected to the cable modem.  So it seems to be a problem with my Deco unit(s).

In addition to the above, I've tried the following:

• I turned off all the Deco nodes and reset one of them by holding the reset button on the bottom.  Then I connected that to power and the cable model and set it up again from scratch.  This didn't work -- the wifi network is available but there is no Internet connectivity.  I didn't use the mesh portion for this, only one node connected directly to the cable modem, to rule out problems with the mesh.
• I've rebooted the cable modem multiple times in case it's hanging onto the MAC address of the last device that was connected.  That doesn't help.
• I updated the firmware on the Deco node I was testing to the latest (1.4.0 Build 20240418), but that didn't help either.

I would love help as I'm pretty stumped at this point.