Issue with firebase authentication error

[Anu-sarath]

Hi Yogesh,
Thanks for sharing excellent application, i have deployed locally the application but authentication failed with below error on login page. I am new to full stack development. Can you please help on how to fix this issue.

{"error":{"code":400,"message":"API key not valid. Please pass a valid API key.","errors":[{"message":"API key not valid. Please pass a valid API key.","domain":"global","reason":"badRequest"}],"status":"INVALID_ARGUMENT"}}

Thanks,
Anusha