AX2700/CAX30 DHCP stopped assigning IP addresses to devices

[gbgadgets]

Device:  CAX30 Cable Modem Router

Firmware Version(s):  1.4.10.8 and 1.4.10.4

Issue:  DHCP stopped successfully assigning IP addresses to devices both wired and wireless unless the device has been setup to receive/request a static IP.  

Expected:  DHCP should assign an IP to any device that requests one if it is not already assigned to a devic and is available.

Attempted Solutions:  Restart modem; Factory reset and reconfigure modem; Restart device(s); Reset devices network settings (forget network, reset netowrk settings)

Workaround:  Set a static IP request from the device if possible (some IOT devices do not provide an interface for requesting a static address and so this does not work for them).

Other possible workaround I have not tried:  Setup a new network SSID instead of using the original SSID for wireless devices.  This was mentioned in another thread of a way to get wireless devices to be successfully assigned an IP, but I do not really want to do this because of the number of devices with setttings to reconfigure, and I think it was reported the problem eventually came back for the new SSID where devices could not successfully get a dynamic IP assigned from DHCP server.

[FURRYe38]

Has a factory reset and setup from scratch been performed since last FW update?

Have you changed the default DHCP IP address pool to 192.168.1.100 to .200? 
The try setting up some IP address reservations for some of your devices? 

[gbgadgets]

Yes, a factory reset and setup from scratch since the last FW update has been performed.  This has not resolved or changed the issue.

Yes, I have changed the IP address pool range and setup some static address assignments for those devices that have that network configuration option, and as mentioned in the issue report above, assigning static addresses does resolve the connection issue(s) for those devices, but this does not solve the issue for a device that do not have the ability to set a static IP, like many IOT devices (Nest thermostat, Kasa Smart switches, etc.)

 The issue appears to be something related to the SSID in combination with DHCP Server of the router.  A factory reset of the IOT devices and setup from scratch does not resolve the issue, hence the router must be persisting something related to DHCP and SSID for these devices to be unable to connect after both have been factory reset and reconfigured.