This may not be an answer and I cannot make any comments yet, but can you try to provide the Javascript code before being compiled by webpack?

Additionally, can you provide the error message coming from the exception? I would like to know the contents of Log::info($e->getMessage());

As for the configuration, as long as the service account has access to the firebase project, it should be fine.

Double check if your firebase_credentials.json exists and laravel can access that file.