Google Assistant - Can't add to Home app

Hi all - I had the Google Assistant integration working between my Google Home and Home Assistant for a couple months. I noticed today it wasn’t working. I suspect the cause of it breaking was changes to my firewall configuration that must have broken port forwarding (now, I believe, resolved). Anyway, where I’m at:

  • GCP gives a OPEN_AUTH_FAILURE in its logs
  • HASS doesn’t register any problems
  • I’m using duckDNS for DDNS. I can reach from outside my network (it doesn’t work on my local network which i believe is a normal limitation? and would not affect this situation)
  • In the Home app, when I go to link devices (it was the same before I removed the link) I get “Site can’t be reached.{lots of stuff} might be temporarily down or it may have moved permanently to a new web address ERR_FAILED”
  • However when I got to in a web browser (via VPN outside my network), I get “Error: Message format incorrect: required key not provided @ data[‘client_id’]” which seems like the right error considering I purposefully didn’t give it the right parameters

Any suggestions on what I can try here? Thanks

This configuration changed recently. Have a look at the integration instruction again and crosscheck.

Thanks for the quick response. Any idea what changed? Do I need to pull new Google Assistant code? Or just check the settings?

Well mine also broke and when i checked it turned out some keys were no longer required and something else was required. just check the installation process and see if yours is the same now.

I unfortunately can’t find anything that is different in the settings. I’m trying not to break stuff my making too many changes…

One additional thing I have noticed. I can get to HASS on my phone in incognito at

However, on normal Chrome I get the Home Assistant logo and it says “unable to connect to home assistant”

Ok so got past the incognito thing by doing agressive cache and storage cleaning from the Home and Chrome apps on my Android phone. That got me to the HomeAssistant login screen when linking from my Home app. I logged in and it redirected a couple times but didn’t finish or succeed, just failed silently.

Finally in clicking around I noticed my SSL cert was expired. Renewing the cert fixed everything. So if anyone else is having this issue, check your SSL cert…