### Operating System Windows 11 ### Environment (if applicable) Chrome ### Firebase SDK Version 12.0.0 ### Firebase SDK Product(s) AppCheck, Auth ### Project Tooling Next.js app ### Detailed Problem Description When AppCheck enforcement is enabled for Authentication, SMS-based sign-in stops working. This happens specifically when Firebase initializes App Check using the ReCaptchaEnterpriseProvider. However, if App Check is initialized with ReCaptchaV3Provider, SMS-based authentication works correctly with any site key configured in Firebase Console → Authentication → Settings → reCAPTCHA (v3, v2 challenge, or Enterprise). If App Check is initialized with ReCaptchaEnterpriseProvider, SMS-based auth only works when the reCAPTCHA Web keys in Firebase Console → Authentication → Settings → reCAPTCHA are set to None. In that case, the SMS code is received and verification succeeds. This leads to the question: What is the correct configuration for using App Check with reCAPTCHA Enterprise and Phone Authentication? ### Steps and code to reproduce issue 1. Generate a reCAPTCHA Enterprise Site Key in the Google Cloud Console. Initialize Firebase App Check using this Enterprise site key with ReCaptchaEnterpriseProvider. 2. Separately, generate a reCAPTCHA v3 site key at https://www.google.com/recaptcha. 3. In the Firebase Console, go to: Authentication → Settings → reCAPTCHA For Web, configure the phone authentication protection using either: reCAPTCHA v3, reCAPTCHA v2 (challenge) or reCAPTCHA Enterprise (Both keys fail when App Check is initialized with the Enterprise provider.)