I've just been started integrating assistant to smarthome project that i'm working on. And I've initially experimenting the assistant by implementing account linking flow and sync intent. I tested the account linking by testing with the google developer tool for oauth flow and confirmed it worked. Whereas, in the smarthome app, upon account linking, as soon as it completes the account linking flow I keep receiving an error message stating "Couldn't update your settings, Check your connection". Didn't find much clue with the logs for troubleshoot. And also, the solutions they were on the other posts does not seem to be working out for me as well. Would appreciate if anyone could help resolve this.
Also, I'd like to know the place where I can find the fulfillment URL that needs to be entered when creating the smarthome action. I've been using firebase to deploy my cloud functions. Moreover, I suspect weather the fulfillment URL I entered that was provided by codelabs sample were invalid thus assisant unable reach the fulfillment.
Your fulfillment URLs are the functions that you've created. For Firebase, there's a specific pattern that you can follow. If you visit your Firebase console, in the functions section, you'll see the full URL which you can copy and paste into the Fulfillment URL input.
In my example, I have a cloud function named "about_info" with the pattern
https://us-central1.PROJECT_ID.cloudfunctions.net/FUNCTION_NAME. So you can use a similar scheme to identify what your function names will be.