How to Use reCAPTCHA Enterprise with Firebase Phone Authentication

[kitta07]

## How to Use reCAPTCHA Enterprise with Firebase Phone Authentication

### Environment

- Firebase JavaScript SDK: version 11.6.0

### Steps I've followed:

1. **Created reCAPTCHA Enterprise key in the GCP console:**
- [GCP reCAPTCHA Enterprise Console](https://console.cloud.google.com/security/recaptcha)

2. **Registered reCAPTCHA Enterprise in Firebase Console App Check:**
- Under the "Apps" tab in Firebase App Check settings.

3. **Applied Authentication in Firebase App Check:**
- Under the "API" tab in Firebase App Check settings.

4. **Configured via Admin SDK (`updateProjectConfig` method):**

```javascript
const projectConfig = await admin.auth().projectConfigManager().updateProjectConfig({
recaptchaConfig: {
phoneEnforcementState: 'ENFORCE',
useSmsTollFraudProtection: true,
useSmsBotScore: true,
}
});
```

5. **Executed `signInWithPhoneNumber` on the frontend (without the third argument):**

Request URL:
```
<URL Removed by Staff>
```

Response:
```json
{
"error": {
"code": 500,
"message": "Internal error encountered.",
"status": "INTERNAL"
}
}
```

### When switching `phoneEnforcementState` to `OFF`

Admin SDK configuration:
```javascript
const projectConfig = await admin.auth().projectConfigManager().updateProjectConfig({
recaptchaConfig: {
phoneEnforcementState: 'OFF',
useSmsTollFraudProtection: false,
useSmsBotScore: false,
}
});
```

Response becomes:

```json
{
"recaptchaEnforcementState": [
{
"provider": "EMAIL_PASSWORD_PROVIDER",
"enforcementState": "ENFORCEMENT_STATE_UNSPECIFIED"
},
{
"provider": "PHONE_PROVIDER",
"enforcementState": "OFF"
}
],
"useSmsBotScore": false,
"useSmsTollFraudProtection": false
}
```

### Question

I want to enable reCAPTCHA Enterprise for Firebase Phone Authentication, but I keep receiving a `500 Internal error`. Is there anything I'm missing or doing incorrectly?