Correct WiFi password not being recognized,​We have been unable to connect.

There's a couple of things you can look at that may help.

Can you see the SSID name broadcast by your WiFi network from the device?  That's the first thing to check.  Xfinity radios can die.

 

Try changing broadcast SSID with the phone app, then try to connect a device that is currently not connecting to it.  Verifies two things.  You are trying to connect to what you think you are (a neighbor isn't spoofing your WiFi connection name), and it's a new network connection if your gateway firmware crashed and did a new hardware encryption key-gen when it came back up.

WiFi security mode may have also defaulted the encryption to WPA3.  Most phones and new PC's can do this, older devices aren't going to be able to, and use WPA2.  Both are currently considered secure.  They won't document their phone app, and the link below may be outdated.  You might have to check this from the phone app now if the option does not appear if you log into your gateway at http://10.0.0.1 See:  https://www.xfinity.com/support/articles/change-wifi-security-mode  Try setting WPA2, then "forget" the wireless connection and rejoin.

Going down the rabbit hole deeper:  There are different WiFi standards.  https://www.lifewire.com/wireless-standards-802-11a-802-11b-g-n-and-802-11ac-816553 to get devices to talk to each other, they need to speak the same standard.  Factory default on newer Xfinity gear will change to 802.11 ax (wifi 6).  A firmware push may have set it to that.  From the phone app, you can try changing that:  https://www.xfinity.com/support/articles/xfi-advanced-settings  802.11 ac can possibly be compatible with older devices that use 802.11n -- but the devil is in the details.  Some firmware can't do both at the same time.  Previously, factory default was 802.11 ac (WiFi 5). 

Older gear will probably be able to speak 802.11 b/g/n.  IOT devices tend to be just 802.11 b.  You can look up model numbers and see what they have for a radio.  If your device is 802.11 b/g/n, then you want to Separate 2.4 and 5G signals.  Pick a different SSID for each one (yourWiFi_SSID_2.4G, yourWiFi_SSID_5G).  *You won't be able to change WiFi standards if you use Xfinity pods.  If it worked before, and now it does not, this won't work for you. 

I guess I'd start there.

Hang on.  Maybe you are one of these:  https://forums.xfinity.com/conversations/your-home-network/resolved-xfinity-internet-customers-should-now-be-able-to-connect-to-their-wifi/640746f541879c3c4d1ba279

They might have bricked your WiFi.  They say "resolved".  Is it??

Hello @user_cb35fa! Thanks so much for taking a moment out of your day to leave a post on our community forum. I see our awesome community members are assisting, and I wanted to check in and see if your concern has been addressed. Let us know, we just want to make sure you get taken care of.