Chromecast suddenly refuses to connect to WLAN

[robert76]

We have been using this chromecast for years, but this evening all of a sudden, the thing is not connected to the WiFi (while a few days ago it worked just fine). Nothing has changed in my setup or my WiFi. I have resetted the Chromecast device twice, have de-installed and re-installed the GHome app, etc. nothing seems to work. Help!

[Ashepherdson]

You have factory reset the Chromecast and re set it up or power cycled it?  Did you power cycle your router?  

[robert76]

I didn't touch my router. Note that none of my devices have connection issues. 

I resetted the chromecast back to factory,  and set it up again using my Google Home app.

[Ashepherdson · Accepted solution]

You should reboot your router to see if that corrects the issue.  

What exactly happens , you said you factory reset the Chromecast, so it's getting a connection, when you try to cast something what happens. 

[robert76]

The thing is that none of the other devices in the house have issues,  and nothing changed with the router. So I'm not too eager to touch the router. It must be something in the chromecast that's causing this issue.

[Ashepherdson]

Rebooting your router is a normal thing to do . It's like step one in troubleshooting , as it could be something in the router blocking the Chromecast.  Anyways you didn't answer my question about the chromecast and what exactly is happening.. you said you set it up (which it can only do on wifi) ..yet it's not connected. So what exactly is happening..when you try to cast what do you see?  Are all devices on the same network, with no vpns or similar?

[robert76]

I don't know. The chromecast won't connect. That's what it says.

[Ashepherdson]

The Chromecast says this..or it shows up on your phone ? 

[Ashepherdson]

Does the Chromecast have any sort of error message...so on your TV is it saying it's connected to wifi , is the date and time showing along with the weather ?

[robert76]

The phone (home app) seems to connect to the chromecast, bug then the message pops up:

 Chromecast was successfully set up, but cannot be found. Make sure your mobile device and chromecast are connected to the same wlan. 

And then it says something about AP isolation...?

[Ashepherdson]

So could be a Wi-Fi issue, if your router has multiple bands (ie a 2.4ghz and 5gz network) , or if you have a mesh network,AP isolation has to be off so that devices can all work together.   Saying all this.. I strongly recommend you power cycle your router to see if that fixes the issue.  

[robert76]

Ok, and how do I "power cycle " my router?

[Ashepherdson]

Unplug the power for 10 seconds or so, then plug it back it and let it boot up