[cloud_firestore]: The service is currently unavailable.

[rbargux]

Is there an existing issue for this?

• I have searched the existing issues.

Which plugins are affected?

Other

Which platforms are affected?

iOS

Description

When trying to query Firestore data on some iOS devices, I'm encountering this error:

The service is currently unavailable. This is most likely a transient condition and may be corrected by retrying with a backoff.

The strange thing is that it's constant; even with a backoff function implemented, the error persists. Furthermore, it only happens when I use specific combinations in my query, which is even stranger since it's the same code. I mean, if I use collection('app_setup').doc('features') it works, but if I use collection('app_setup').doc('status') it doesn't work and throws the error above.

The functions I'm using for the query are:

Future<T?> retry<T>(
    Future<T?> Function() callback,
  {
    int maxRetries = 4,
    Duration timeout = const Duration(seconds: 5),
  }) async {
    int retryCount = 0;

    while (retryCount < maxRetries) {
      try {
        return await callback().timeout(timeout);
      } on FirebaseException catch (e) {
        if (e.code == 'unavailable') {
          retryCount++;
          int delay = 1 << retryCount;
          await Future<void>.delayed(Duration(seconds: delay));
        } else {
          rethrow;
        }
      } on TimeoutException {
        retryCount++;
      }
    }
    return null;
  }

Future<Map<String, dynamic>?> readFeatures() async {
  DocumentReference<Map<String, dynamic>>? docRef = database
      ?.collection('app_setup')
      .doc('features');
  DocumentSnapshot<Map<String, dynamic>>? doc = await docRef?.get();

  return doc?.data();
}

Future<Map<String, dynamic>?> readStatus() async {
  DocumentReference<Map<String, dynamic>>? docRef = database
      ?.collection('app_setup')
      .doc('status');
  DocumentSnapshot<Map<String, dynamic>>? doc = await docRef?.get();

  return doc?.data();
}

 👍  Map<String, dynamic>? response = await ref
            .read(appConstantsProvider.notifier)
            .retry(readFeatures);

👎  Map<String, dynamic>? response = await ref
            .read(appConstantsProvider.notifier)
            .retry(readStatus);

Some logs

👍

👎

Flutter doctor

[✓] Flutter (Channel stable, 3.35.6, on macOS 26.2 25C56 darwin-arm64, locale en-US)
[✓] Android toolchain - develop for Android devices (Android SDK version 36.1.0)
[✓] Xcode - develop for iOS and macOS (Xcode 26.2)
[✓] Chrome - develop for the web
[✓] Android Studio (version 2025.2)
[✓] VS Code (version 1.106.3)

firebase_core: "4.2.1"
cloud_firestore: "6.1.0"

Reproducing the issue

basic flutter create and GoogleService-Info.plist

Firebase Core version

4.2.1

Flutter Version

3.35.6

Relevant Log Output

Flutter dependencies

No response

Additional context and comments

No response

[SelaseKay]

Hi @rbargux, thanks for the report. This appears to be a network-related issue rather than something directly caused by flutterfire. Could you please take a look at this comment and see if it helps in your case?

[rbargux]

Thank you so much for the quick response. This was the first thing I thought was happening, but we tried switching between mobile data and Wi-Fi, then to other networks, and the problem persists.

It's very strange, as I also reported above. When I check a combination in the FireStore app_setup>features, it works correctly, but when I run app_setup>status, it returns this error. Another curious detail is that we have the same connection in the office, and this only happens to one person.

P.S.: They don't have iCloud+, low battery, or the low data mode option in the network settings.

[SelaseKay]

Hi @rbargux, it may be a device-specific issue. What device is the person using?

[rbargux]

Thanks for response, devices that currently present this issue are:

iPhone SE - iOS 26.2.1
iPhone 14 Pro - iOS 26.2.1

[irchriscott]

I am also facing the same issue. Everything was working great until it stopped working. I am using Google Pixel 9 Pro XL.
I don't think it is a network issue as I have external endpoints and they working well. Other Firebase services are also working well (Auth, Messaging, etc.)
The funny thing is it only fails when writing to the collection. I even tried to disable the security features on firebase dashboard to allow even unauthenticated users to perform read and writes operations, still doesn't work. After one failed write, even other read operations don't work until the app is restarted.

[Lyokone]

Hey, thanks for reporting!

The "service is currently unavailable" error comes from the Firestore backend, not the FlutterFire SDK. This is typically a network/firewall issue on specific devices or regions. I'd recommend checking https://status.firebase.google.com/ and trying on a different network.

Closing as this isn't a FlutterFire issue — if you believe it is, feel free to reopen with more details.