reCAPTCHA Enterprise MFA not triggering challengeAccount UI even with requestToken

Hi,

I am integrating reCAPTCHA Enterprise with Account Verification (MFA).

Flow:
1. Frontend calls grecaptcha.enterprise.execute() with action LOGIN and twofactor: true
2. Backend calls createAssessment with accountVerification enabled
3. Response contains accountVerification with requestToken
4. When I call grecaptcha.enterprise.challengeAccount() with:
- account-token
- container

However:
- No popup UI is rendered
- No verification code is sent

Code snippet:

const triggerMFA = async (requestToken: string): Promise<string> => {

 if (!window.grecaptcha?.enterprise) {
 throw new Error("reCAPTCHA not ready");
 }
 return window.grecaptcha.enterprise.challengeAccount(
 import.meta.env.VITE_RECAPTCHA_SITE_KEY, {
 'account-token': requestToken, // requestToken is coming from Account verification
 'container': 'mfa-container', // Binded to div in log-in page
 }
 );
};

Sample Response:

{
 ...,
 "accountVerification": {
 "endpoints": [{
 "emailAddress": " [removed by moderator] ",
 "requestToken": "tplIUFvvJUIpLaOH0hIVj2H71t5Z9mDK2RhB1SAGSIUOgOIsBv",
 "lastVerificationTime": "",
 }],
 "latestVerificationResult": "RESULT_UNSPECIFIED"
 }
}

Technologies:Front End - ReactBack End - Spring BootHere are list of questions I have:1. Under what exact conditions does challengeAccount() render UI?

2. Is it correct that challengeAccount only works when riskAnalysis.challenge = "CHALLENGE_REQUIRED"?

3. Is there any way to force MFA challenge for testing?

4. Does MFA depend entirely on Google’s risk engine ?