The error thrown when the user needs to provide a second factor to sign in successfully.
The error code for this error is auth/multi-factor-auth-required.
Signature:
export interface MultiFactorError extends AuthError 
Extends: AuthError
Properties
| Property | Type | Description | 
|---|---|---|
| customData | AuthError['customData'] & { readonly operationType: (typeof OperationTypeMap)[keyof typeof OperationTypeMap]; } | Details about the MultiFactorError. | 
MultiFactorError.customData
Details about the MultiFactorError.
Signature:
readonly customData: AuthError['customData'] & {
        readonly operationType: (typeof OperationTypeMap)[keyof typeof OperationTypeMap];
    };
Example
let resolver;
let multiFactorHints;
signInWithEmailAndPassword(auth, email, password)
    .then((result) => {
      // User signed in. No 2nd factor challenge is needed.
    })
    .catch((error) => {
      if (error.code == 'auth/multi-factor-auth-required') {
        resolver = getMultiFactorResolver(auth, error);
        multiFactorHints = resolver.hints;
      } else {
        // Handle other errors.
      }
    });
// Obtain a multiFactorAssertion by verifying the second factor.
const userCredential = await resolver.resolveSignIn(multiFactorAssertion);