diff --git a/packages/firebase_ui_auth/lib/src/mfa.dart b/packages/firebase_ui_auth/lib/src/mfa.dart
index f086aa44..e6d1fa85 100644
--- a/packages/firebase_ui_auth/lib/src/mfa.dart
+++ b/packages/firebase_ui_auth/lib/src/mfa.dart
@@ -5,6 +5,7 @@
 import 'dart:async';
 
 import 'package:firebase_auth/firebase_auth.dart' as fba;
+import 'package:firebase_core/firebase_core.dart';
 import 'package:firebase_ui_auth/firebase_ui_auth.dart';
 import 'package:firebase_ui_auth/src/widgets/internal/universal_page_route.dart';
 import 'package:flutter/scheduler.dart';
@@ -23,12 +24,15 @@ Future<fba.UserCredential> startMFAVerification({
   required fba.MultiFactorResolver resolver,
   fba.FirebaseAuth? auth,
   SMSCodeInputScreenBuilder? smsCodeInputScreenBuilder,
+  void Function(FirebaseException e)? onError,
 }) async {
   if (resolver.hints.first is fba.PhoneMultiFactorInfo) {
     return startPhoneMFAVerification(
       context: context,
       resolver: resolver,
       auth: auth,
+      smsCodeInputScreenBuilder: smsCodeInputScreenBuilder,
+      onError: onError,
     );
   } else {
     throw Exception('Unsupported MFA type');
@@ -40,10 +44,12 @@ Future<fba.UserCredential> startPhoneMFAVerification({
   required fba.MultiFactorResolver resolver,
   fba.FirebaseAuth? auth,
   SMSCodeInputScreenBuilder? smsCodeInputScreenBuilder,
+  void Function(FirebaseException e)? onError,
 }) async {
   final session = resolver.session;
   final hint = resolver.hints.first;
   final completer = Completer<fba.UserCredential>();
+
   final navigator = Navigator.of(context);
 
   final provider = PhoneAuthProvider();
@@ -60,14 +66,19 @@ Future<fba.UserCredential> startPhoneMFAVerification({
   final flowKey = Object();
 
   final actions = [
-    AuthStateChangeAction<CredentialReceived>((context, inner) {
+    AuthStateChangeAction<CredentialReceived>((context, inner) async {
       final cred = inner.credential as fba.PhoneAuthCredential;
       final assertion = fba.PhoneMultiFactorGenerator.getAssertion(cred);
       try {
-        final cred = resolver.resolveSignIn(assertion);
-        completer.complete(cred);
+        final cred = await resolver.resolveSignIn(assertion);
+        if (!completer.isCompleted) {
+          completer.complete(cred);
+        }
       } catch (e) {
-        completer.completeError(e);
+        if (e is FirebaseException) {
+          onError?.call(e);
+        }
+        flow.onError(e);
       }
     }),
   ];
@@ -100,6 +111,7 @@ Future<fba.UserCredential> startPhoneMFAVerification({
     }
 
     return AuthFlowBuilder<PhoneAuthController>(
+      auth: auth,
       flow: flow,
       flowKey: flowKey,
       child: child,
diff --git a/packages/firebase_ui_auth/test/mfa_test.dart b/packages/firebase_ui_auth/test/mfa_test.dart
new file mode 100644
index 00000000..3ef82336
--- /dev/null
+++ b/packages/firebase_ui_auth/test/mfa_test.dart
@@ -0,0 +1,197 @@
+// Copyright 2022, the Chromium project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'package:firebase_auth/firebase_auth.dart' as fba;
+import 'package:firebase_core/firebase_core.dart';
+import 'package:firebase_ui_auth/firebase_ui_auth.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mockito/mockito.dart';
+
+import 'test_utils.dart';
+
+class MockPhoneMultiFactorInfo extends Mock
+    implements fba.PhoneMultiFactorInfo {
+  @override
+  String get phoneNumber => '+1234567890';
+}
+
+class MockTotpMultiFactorInfo extends Mock implements fba.TotpMultiFactorInfo {}
+
+class MockMultiFactorSession extends Mock implements fba.MultiFactorSession {}
+
+class MockMultiFactorResolver extends Mock implements fba.MultiFactorResolver {
+  final MockMultiFactorSession _session = MockMultiFactorSession();
+  final List<fba.MultiFactorInfo> _hints = [MockPhoneMultiFactorInfo()];
+
+  @override
+  fba.MultiFactorSession get session => _session;
+
+  @override
+  List<fba.MultiFactorInfo> get hints => _hints;
+
+  @override
+  Future<fba.UserCredential> resolveSignIn(
+    fba.MultiFactorAssertion? assertion,
+  ) {
+    return super.noSuchMethod(
+      Invocation.method(#resolveSignIn, [assertion]),
+      returnValue: Future.value(MockCredential()),
+      returnValueForMissingStub: Future.value(MockCredential()),
+    );
+  }
+}
+
+class MockUnsupportedMultiFactorResolver extends Mock
+    implements fba.MultiFactorResolver {
+  @override
+  List<fba.MultiFactorInfo> get hints => [MockTotpMultiFactorInfo()];
+}
+
+class MockPhoneAuthCredential extends Mock implements fba.PhoneAuthCredential {}
+
+void main() {
+  group('startMFAVerification', () {
+    late MockAuth auth;
+    late MockMultiFactorResolver resolver;
+
+    setUpAll(() {
+      setFirebaseUiIsTestMode(true);
+    });
+
+    setUp(() {
+      auth = MockAuth();
+      resolver = MockMultiFactorResolver();
+    });
+
+    testWidgets('throws on unsupported MFA type', (tester) async {
+      final unsupportedResolver = MockUnsupportedMultiFactorResolver();
+      await tester.pumpWidget(
+        MaterialApp(
+          home: Builder(
+            builder: (context) {
+              return ElevatedButton(
+                onPressed: () {
+                  expect(
+                    () => startMFAVerification(
+                      context: context,
+                      resolver: unsupportedResolver,
+                      auth: auth,
+                    ),
+                    throwsA(isA<Exception>()),
+                  );
+                },
+                child: const Text('Start MFA'),
+              );
+            },
+          ),
+        ),
+      );
+
+      await tester.tap(find.text('Start MFA'));
+    });
+
+    testWidgets(
+      'handles resolveSignIn error, calls onError, propagates to flow, and succeeds on retry',
+      (tester) async {
+        final expectedCredential = MockCredential();
+        final testException = fba.FirebaseAuthException(
+          code: 'invalid-verification-code',
+          message: 'Invalid code',
+        );
+
+        int resolveCallCount = 0;
+        when(resolver.resolveSignIn(any)).thenAnswer((_) async {
+          resolveCallCount++;
+          if (resolveCallCount == 1) {
+            throw testException;
+          }
+          return expectedCredential;
+        });
+
+        FirebaseException? capturedError;
+        late List<FirebaseUIAction> capturedActions;
+        late Object capturedFlowKey;
+
+        Future<fba.UserCredential>? verificationFuture;
+
+        await tester.pumpWidget(
+          MaterialApp(
+            home: Builder(
+              builder: (context) {
+                return ElevatedButton(
+                  onPressed: () {
+                    verificationFuture = startMFAVerification(
+                      context: context,
+                      resolver: resolver,
+                      auth: auth,
+                      onError: (e) {
+                        capturedError = e;
+                      },
+                      smsCodeInputScreenBuilder:
+                          (context, actions, flowKey, action) {
+                            capturedActions = actions;
+                            capturedFlowKey = flowKey;
+                            return const Scaffold(
+                              body: Text('Custom SMS Code Input Screen'),
+                            );
+                          },
+                    );
+                  },
+                  child: const Text('Start MFA'),
+                );
+              },
+            ),
+          ),
+        );
+
+        // Tap the button to start MFA verification
+        await tester.tap(find.text('Start MFA'));
+        await tester.pumpAndSettle();
+
+        expect(find.text('Custom SMS Code Input Screen'), findsOneWidget);
+        expect(capturedActions, isNotEmpty);
+
+        final credentialAction = capturedActions
+            .whereType<AuthStateChangeAction<CredentialReceived>>()
+            .first;
+
+        final mockPhoneCred = MockPhoneAuthCredential();
+
+        // 1st attempt: throws error
+        credentialAction.callback(
+          tester.element(find.text('Custom SMS Code Input Screen')),
+          CredentialReceived(mockPhoneCred),
+        );
+        await tester.pumpAndSettle();
+
+        expect(resolveCallCount, 1);
+        expect(capturedError, equals(testException));
+
+        // Verify flow state transitioned to AuthFailed
+        final state = AuthFlowBuilder.getState(capturedFlowKey);
+        expect(state, isA<AuthFailed>());
+        expect((state as AuthFailed).exception, equals(testException));
+
+        // Screen should still be visible because we did not pop on error
+        expect(find.text('Custom SMS Code Input Screen'), findsOneWidget);
+
+        // 2nd attempt: succeeds
+        credentialAction.callback(
+          tester.element(find.text('Custom SMS Code Input Screen')),
+          CredentialReceived(mockPhoneCred),
+        );
+        await tester.pumpAndSettle();
+
+        expect(resolveCallCount, 2);
+        // Screen should now be popped
+        expect(find.text('Custom SMS Code Input Screen'), findsNothing);
+
+        expect(verificationFuture, isNotNull);
+        final result = await verificationFuture!;
+        expect(result, equals(expectedCredential));
+      },
+    );
+  });
+}
diff --git a/packages/firebase_ui_auth/test/test_utils.dart b/packages/firebase_ui_auth/test/test_utils.dart
index df0c7164..484671a3 100644
--- a/packages/firebase_ui_auth/test/test_utils.dart
+++ b/packages/firebase_ui_auth/test/test_utils.dart
@@ -198,6 +198,20 @@ class MockAuth extends Mock implements fba.FirebaseAuth {
       }),
     );
   }
+
+  @override
+  Future<fba.ConfirmationResult> signInWithPhoneNumber(
+    String? phoneNumber, [
+    fba.RecaptchaVerifier? verifier,
+  ]) async {
+    return super.noSuchMethod(
+      Invocation.method(#signInWithPhoneNumber, [phoneNumber, verifier]),
+      returnValue: Future.value(MockConfirmationResult()),
+      returnValueForMissingStub: Future.value(MockConfirmationResult()),
+    );
+  }
 }
 
+class MockConfirmationResult extends Mock implements fba.ConfirmationResult {}
+
 class TestException implements Exception {}