> ## Documentation Index > Fetch the complete documentation index at: https://cometchat-22654f5b-docs-llms-scoped-indexes.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # Troubleshooting > Troubleshoot CometChat Flutter UI Kit V6 setup, login, theming, styling, messaging, calling, navigation, and build issues. | Field | Value | | - | - | | Package | `cometchat_chat_uikit` | | Import | `import 'package:cometchat_chat_uikit/cometchat_chat_uikit.dart';` | | Purpose | Troubleshoot CometChat Flutter UI Kit V6 setup, login, theming, styling, messaging, calling, navigation, and build issues. | | Key classes | `CometChatUIKit` · `CometChatIncomingMessageBubbleStyle` · `CometChatMentionsFormatter` · `CometChatMessageList` · `CometChatOutgoingMessageBubbleStyle` | | Related | [Getting Started With CometChat Flutter UI Kit V6](/ui-kit/flutter/getting-started) | ## Initialization and Login | Symptom | Cause | Fix | | - | - | - | | `CometChatUIKit.init()` fails silently | Invalid App ID, Region, or Auth Key | Double-check credentials from the [CometChat Dashboard](https://app.cometchat.com/) | | Blank screen after login | Component rendered before `init()` or `login()` completes | Ensure `init()` → `login()` order completes before rendering any UI Kit component. See [Methods](/ui-kit/flutter/methods) | | Component renders but shows no data | User not logged in | Call `CometChatUIKit.login("UID")` after init resolves | | Login fails with "UID not found" | UID doesn't exist in your CometChat app | Create the user via Dashboard, SDK, or REST API first | | `CometChatUIKit.loggedInUser` returns null | User not logged in or session expired | Call `login()` or `loginWithAuthToken()` first | | Auth Key exposed in production | Using Auth Key instead of Auth Token | Switch to `loginWithAuthToken()` for production. Generate tokens server-side via the REST API | *** ## Theming and Styling | Symptom | Cause | Fix | | - | - | - | | Theme not applied | `ThemeExtension` not added to `MaterialApp` | Add CometChat style extensions to your `ThemeData.extensions` list | | Dark mode not working | Brightness not detected | CometChat theme uses `MediaQuery.platformBrightnessOf(context)`. Ensure your `MaterialApp` supports dark mode | | Custom colors not applying | Overriding wrong style class | Check [Component Styling](/ui-kit/flutter/component-styling) for the correct style class per component | | Component-level style ignored | Style object not passed correctly | Ensure you pass the style to the `style` property, not as a `ThemeExtension` | | Styles apply in light mode but not dark | Only light theme configured | Configure both light and dark themes in `MaterialApp` with separate `ThemeData` instances | | Bubble style not applying | Style linked to wrong direction | Define separate styles for `CometChatOutgoingMessageBubbleStyle` and `CometChatIncomingMessageBubbleStyle` — changing one does not affect the other | *** ## Components | Symptom | Cause | Fix | | - | - | - | | Component not rendering | `init()` or `login()` not complete | Ensure both complete before building any CometChat widget | | Message list is empty | Invalid `User` or `Group` object | Fetch the user or group via the SDK before passing it to the component | | `onThreadRepliesClick` not firing | Callback not set | Pass the callback to `CometChatMessageList(onThreadRepliesClick: ...)` | | Custom template not rendering | Template key doesn't match message | Ensure `type` and `category` on your template match the message's `type` and `category` exactly | | `addTemplate` not overriding default | Template appended, not replaced | `addTemplate` appends to the list. The template map uses last-write-wins by `category_type` key, so your template must have the same key to override | | Keyboard covers composer | `resizeToAvoidBottomInset` not set | Set `resizeToAvoidBottomInset: true` on your `Scaffold` | | Swipe-to-reply not working | Disabled or message not eligible | Check `enableSwipeToReply` is `true`, message has a valid ID, and is not deleted or an action message | | Audio playback issues | Multiple audio states | The UI Kit uses `AudioStateManager` internally. Ensure you're not conflicting with other audio players | *** ## Calling | Symptom | Cause | Fix | | - | - | - | | Call buttons not appearing | Calls not enabled | Ensure `enableCalls = true` is set in your `UIKitSettingsBuilder` | | Incoming call screen not showing | Call listener not registered | Ensure `CometChat.addCallListener()` is called in your app initialization | | Call connects but no audio/video | Missing permissions | Request camera and microphone permissions before initiating calls | *** ## Extensions | Symptom | Cause | Fix | | - | - | - | | Extension feature not appearing | Extension not activated in Dashboard | Enable the specific extension from your [Dashboard](/fundamentals/extensions-overview) | | Stickers not showing | Sticker extension not enabled | Activate [Sticker Extension](/fundamentals/stickers) in Dashboard | | Polls option missing | Polls extension not enabled | Activate [Polls Extension](/fundamentals/polls) in Dashboard | | Link preview not rendering | Link Preview extension not enabled | Activate [Link Preview Extension](/fundamentals/link-preview) in Dashboard | *** ## BLoC and State Management | Symptom | Cause | Fix | | - | - | - | | BLoC already closed error | External BLoC disposed prematurely | If you provide a custom BLoC via `messageListBloc`, ensure it outlives the widget | | State not updating after BLoC event | Event dispatched to wrong BLoC instance | Ensure you're dispatching events to the same BLoC instance the widget is using | | Duplicate messages appearing | Multiple BLoC instances for same conversation | Use a single BLoC instance per conversation. Don't create a new one on every rebuild | *** ## Localization | Symptom | Cause | Fix | | - | - | - | | UI text not translated | Locale not set | Ensure your `MaterialApp` has the correct `locale` and `supportedLocales` configured | | String overrides not appearing | Wrong key | Verify the key matches exactly. See [Localize](/ui-kit/flutter/localize) | *** ## Sound | Symptom | Cause | Fix | | - | - | - | | No sound plays | Sound disabled | Check `disableSoundForMessages` is not set to `true` | | Custom sound not playing | Asset not found | Ensure the sound file is added to your `pubspec.yaml` assets and the path is correct | *** ## Text Formatters | Symptom | Cause | Fix | | - | - | - | | Mentions render as plain text | Formatter not added | Pass `CometChatMentionsFormatter()` in the `textFormatters` list | | `textFormatters` has no effect | Empty list passed | Add at least one formatter to the list | | Markdown not rendering | `MarkdownTextFormatter` not included | Add `MarkdownTextFormatter()` to your `textFormatters` list or use `RichTextConfiguration` on the composer | *** ## Events | Symptom | Cause | Fix | | - | - | - | | Event listener not firing | Subscribed to wrong event class | Check the [Events](/ui-kit/flutter/events) page for exact event class names | | Duplicate event triggers | Multiple registrations without cleanup | Remove listeners when the widget is disposed | | Listener ID collision | Non-unique listener tag | Use a unique string for each listener registration | This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.