Honeywell T9 Thermostat WiFi Not Connecting

For the past year, my Honeywell T9 thermostat had no issues connecting to my wi-fi. It suddenly stopped connecting last night and will not reconnect. In fact, the thermostat no longer sees my SSIDs (broadcast is enabled) for either the 2.4Ghz or 5GHz networks (it can connect to either). But it does see the SSIDs of my neighbors. When I manually enter my SSID and password, it gives an error saying it cannot connect. I have turned off xFI Advanced Protection, rebooted the Xfinity router several times, and did a factory reset of the thermostat. I do not have any problem with any other device (this is the only Honeywell one). Any suggestions?