Im working with firebase auth to make a login with google. Im try to make the login and consume the google books api with the Oauth 2.0 token. I did the authentication and the authorization process but the when i consume the api with the token generated, the api return me this error.

{
  "error": {
    "code": 401,
    "message": "Request had invalid authentication credentials. Expected OAuth 2 access token, login cookie or other valid authentication credential. See https://developers.google.com/identity/sign-in/web/devconsole-project.",
    "errors": [
      {
        "message": "Invalid Credentials",
        "domain": "global",
        "reason": "authError",
        "location": "Authorization",
        "locationType": "header"
      }
    ],
    "status": "UNAUTHENTICATED"
  }
}

Heres my flow.
I opened the credential manager to get the credentials of google account.

val googleIdOptions = GetGoogleIdOption.Builder()
            .setFilterByAuthorizedAccounts(false)
            .setServerClientId(context.getString(R.string.WEB_CLIENT_ID))
            .setAutoSelectEnabled(true)
            .build()

val credentialRequest = GetCredentialRequest.Builder()
            .addCredentialOption(googleIdOption)
            .build()

val result = CredentialManager.create(context).getCredential(
                request = request,
                context = context,
            )

Then, i cast my credential to type TYPE_GOOGLE_ID_TOKEN_CREDENTIAL and make my firebase auth with credential.

val credential = result.credential
            if (credential.type == GoogleIdTokenCredential.TYPE_GOOGLE_ID_TOKEN_CREDENTIAL) {
                try {
                    val googleIdTokenCredential = GoogleIdTokenCredential.createFrom(credential.data)
                    try {
                        Firebase.auth
                         .signInWithCredential(GoogleAuthProvider.getCredential(googleIdTokenCredential.idToken, null))
                            .addOnCompleteListener {
                                val token = it.result.user?.getIdToken(false)?.result?.token
                                println(token)
                                handlerResult(it, firebaseState)
                            }
                    } catch (e: ApiException) {
                        e.printStackTrace()
                    }
                } catch (e: GoogleIdTokenParsingException) {
                    Log.e(TAG, "Received an invalid google id token response", e)
                }
            }

Then, continue with the Authorization process to the API.

val authorizationRequest = AuthorizationRequest.Builder()
                            .setRequestedScopes(listOf(Scope("https://www.googleapis.com/auth/books")))
                            .build()
                        Identity.getAuthorizationClient(this)
                            .authorize(authorizationRequest)
                            .addOnSuccessListener { authorizationResult ->
                                if (authorizationResult.hasResolution()) {
                                    // Access needs to be granted by the user
                                    val pendingIntent = authorizationResult.pendingIntent
                                    try {
                                        pendingIntent?.let {
                                            launcher.launch(IntentSenderRequest.Builder(it.intentSender).build())
                                        }
                                    } catch (e: SendIntentException) {
                                        Log.e(
                                            "AutenticationActivity",
                                            "Couldn't start Authorization UI: " + e.localizedMessage
                                        )
                                    }
                                } else {
                                    // Access already granted, continue with user action
                                    openMainActivity()
                                }
                            }
                            .addOnFailureListener { e -> Log.e("AutenticationActivity", "Failed to authorize", e) }

And finally, launch with retrofit the Books api.

val token = Firebase.auth.currentUser?.getIdToken(false)?.result?.token
        token.let {
            val myVolumesDTO = services.getMyVolumes(shelf, "Bearer $it")
        }

The callback in the Logcat looks like this.

--> GET https://www.googleapis.com/books/v1/mylibrary/bookshelves/4/volumes
Authorization: Bearer eyJhbGciOiJSUzI1NiIs...
--> END GET

I dont know what im doing wrong. Could someone help me?
Thank you.

I have some configurations in the GCC, i set my oauth clients for the android app and configure my oauth consentment page. Add my ApiKey and add the Books API in the Restricted Apis.