If you can not build the app with Expo, and always have the error when building the app ( the app running in the expo simulator is fine, for example ).
Please open your app building log in the expo, if you see something similar like this:
The error happens when parsing google-services.json, because you use Wilcity google-services.json, not yours.
Please follow to this documentation:
To correct the setting, then start your build again.