GOOGLE_APPLICATION_CREDENTIALS must be defined

Question

I would like to use Google Text-to-Speech but I get the following error:

W/System.err: java.io.IOException: The Application Default Credentials are not available. They are available if running in Google Compute Engine. Otherwise, the environment variable GOOGLE_APPLICATION_CREDENTIALS must be defined pointing to a file defining the credentials. See https://developers.google.com/accounts/docs/application-default-credentials for more information.

I do not understand this, since I have already defined that environment variable. See here:

I have also logged in with gcloud auth application-default login.

Why do I get this error?

Update

This is what happens if I try to log in:

C:\Users\rsaad\AppData\Local\Google\Cloud SDK>gcloud auth application-default login

The environment variable [GOOGLE_APPLICATION_CREDENTIALS] is set to:
[C:\Users\rsaad\AndroidStudioProjects\Kitt\Kitt-0a9a71966cc8.json] Credentials will still be generated to the default location:
[C:\Users\rsaad\AppData\Roaming\gcloud\application_default_credentia ls.json] To use these credentials, unset this environment variable before running your application.

Do you want to continue (Y/n)? y

Your browser has been opened to visit:

https://accounts.google.com/o/oauth2/auth?client_id=764086051850-6qr4p6gpi6hn506pt8ejuq83di341hur.apps.googleusercontent.com&redirect_uri=http%3A%2F%2Flocalhost%3A8085%2F&scope=openid+https%3A%2F%2Fwww.googleapis.com%2Fauth%2Fuserinfo.email+https%3A%2F%2Fwww.googleapis.com%2Fauth%2Fcloud-platform+https%3A%2F%2Fwww.googleapis.com%2Fauth%2Faccounts.reauth&code_challenge=xgtC_woosyFMJXQk6sVWDFqJew9jBAKDEABK_cxEVqc&code_challenge_method=S256&access_type=offline&response_type=code&prompt=select_account

Credentials saved to file: [C:\Users\rsaad\AppData\Roaming\gcloud\application_default_credentials.json]

These credentials will be used by any library that requests Application Default Credentials (ADC). C:\Users\rsaad\AppData\Local\Google\Cloud SDK\google-cloud-sdk\bin..\lib\third_party\google\auth_default.py:69: UserWarning: Your application has authenticated using end user credentials from Google Cloud SDK without a quota project. You might receive a "quota exceeded" or "API not enabled" error. We recommend you rerun gcloud auth application-default login and make sure a quota project is added. Or you can use service accounts instead. For more information about service accounts, see https://cloud.google.com/docs/authentication/
warnings.warn(_CLOUD_SDK_CREDENTIALS_WARNING)

Quota project "kitt-292122" was added to ADC which can be used by Google client libraries for billing and quota. Note that some services may still bill the project owning the resource.