> ## Documentation Index > Fetch the complete documentation index at: https://cometchat-22654f5b-docs-agent-native-development.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # Troubleshooting > Troubleshoot CometChat React UI Kit setup, initialization, login, theming, permissions, messaging, calling, and build issues. | Field | Value | | - | - | | Page type | Troubleshooting reference | | Scope | All CometChat React UI Kit v6 issues — initialization, rendering, theming, calling, extensions, AI features, localization, sound, events | | When to reference | When a component fails to render, data is missing, styling doesn't apply, or a feature doesn't appear | ## 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/) | | Component doesn't render | `init()` not called or not awaited before rendering | Ensure `init()` completes before mounting components. See [Methods](/ui-kit/react/v6/methods) | | Component renders but shows no data | User not logged in | Call `CometChatUIKit.login("UID")` after init | | Login fails with "UID not found" | UID doesn't exist in your CometChat app | Create the user via Dashboard, SDK, or API first | | Blank screen after login | Component mounted before init/login completes | Use state to conditionally render after login resolves | | `getLoggedinUser()` returns null | User not logged in or session expired | Call `login()` or `loginWithAuthToken()` first | | `sendTextMessage()` fails | User not logged in or invalid receiver | Ensure login completes before sending messages | | Auth Key exposed in production | Using Auth Key instead of Auth Token | Switch to [Auth Token](/ui-kit/react/v6/methods#login-using-auth-token) for production | *** ## SSR / Framework-Specific | Symptom | Cause | Fix | | - | - | - | | SSR hydration error | CometChat components use browser APIs (`window`, `WebSocket`, `document`) on server | Wrap in `useEffect` or use dynamic import with `ssr: false`. See [Next.js Integration](/ui-kit/react/v6/next-js-integration) | | CometChat components fail in Astro | Astro SSR tries to render on server | Use `client:only="react"` directive on CometChat islands | *** ## Theming and CSS | Symptom | Cause | Fix | | - | - | - | | CSS/theme not applied | Missing CSS import | Add `@import url("@cometchat/chat-uikit-react/css-variables.css");` in your CSS entry file | | CSS has no effect | Base stylesheet not imported | Add `@import url("@cometchat/chat-uikit-react/css-variables.css");` at top of `App.css` | | Overrides not applying | Missing `.cometchat` scope in selector | Scope overrides under `.cometchat` | | Selectors don't match | Using CSS Modules (hashed class names) | Move rules to a global stylesheet, not `*.module.css` | | Component-level override not working | Missing `.cometchat` parent in selector | Use `.cometchat .cometchat-conversations` not just `.cometchat-conversations` | | Dark mode unchanged | `data-theme` missing or mismatch | Set `data-theme="dark"` on the wrapper and target `.cometchat-root[data-theme="dark"] .cometchat` | | Font not changing | `--cometchat-font-family` set on wrong element | Set on `.cometchat` | | Styles leak into host app | Missing `.cometchat` scope prefix | Always scope overrides under `.cometchat` | | Token change has no visible effect | Token doesn't control the expected property | Check the [Color Resources](/ui-kit/react/v6/theme/color-resources) table | *** ## Components | Symptom | Cause | Fix | | - | - | - | | Callback not firing | Wrong prop name or signature | Check the Actions section on the component page for exact prop name and parameter types | | Custom view not appearing | Returning `null` or `undefined` from view prop | Ensure view function returns valid JSX | | Messages not loading | Invalid user/group object passed | Ensure you fetch the user/group via SDK before passing to components | *** ## Calling | Symptom | Cause | Fix | | - | - | - | | Call buttons not appearing in Message Header | `@cometchat/calls-sdk-javascript` not installed | Run `npm install @cometchat/calls-sdk-javascript` — UI Kit auto-detects it | | Incoming call screen not showing | `CometChatIncomingCall` not mounted in the component tree | Render the component at the app root level so it can listen for incoming calls | *** ## Extensions | Symptom | Cause | Fix | | - | - | - | | Extension feature not appearing | Extension not activated in CometChat Dashboard | Enable the specific extension from your [Dashboard](/fundamentals/extensions-overview) | | Stickers not showing in composer | Sticker extension not enabled | Activate [Sticker Extension](/fundamentals/stickers) in Dashboard | | Polls option missing from action sheet | Polls extension not enabled | Activate [Polls Extension](/fundamentals/polls) in Dashboard | | Link preview not rendering in messages | Link Preview extension not enabled | Activate [Link Preview Extension](/fundamentals/link-preview) in Dashboard | *** ## AI Features | Symptom | Cause | Fix | | - | - | - | | AI features not appearing | Feature not activated in CometChat Dashboard | Enable the specific AI feature from your [Dashboard](/fundamentals/ai-user-copilot/overview) | | Conversation Starter not showing | Feature not enabled or no conversation context | Ensure [Conversation Starter](/fundamentals/ai-user-copilot/conversation-starter) is activated in Dashboard | | Smart Replies not appearing in composer | Feature not enabled in Dashboard | Ensure [Smart Replies](/fundamentals/ai-user-copilot/smart-replies) is activated in Dashboard | *** ## Localization | Symptom | Cause | Fix | | - | - | - | | UI text not translated | Language code not matching supported codes | Check the supported languages table in [Localize](/ui-kit/react/v6/localize) for exact codes (e.g., `en-US` not `en`) | | Custom translations not appearing | `addTranslation` called before `init` | Call `CometChatLocalize.init()` first, then `addTranslation()` | | Date/time format unchanged | `disableDateTimeLocalization` set to `true` | Set `disableDateTimeLocalization: false` in init config | | Component-level CalendarObject ignored | Prop name mismatch | Check the component docs for the exact prop name (e.g., `lastActiveAtDateTimeFormat`) | | Missing translation key shows raw key | No `missingKeyHandler` configured | Add a `missingKeyHandler` function in init config | *** ## Sound | Symptom | Cause | Fix | | - | - | - | | No sound plays | Browser autoplay policy blocks audio before user interaction | `hasInteracted()` must return `true` — the user must interact with the page first | | Custom sound not playing | Invalid file path or unsupported format | Ensure the path is correct and the file is a valid audio format (WAV/MP3) | | Sound keeps playing | `pause()` not called | Call `CometChatSoundManager.pause()` to stop playback | | `Sound` import error | `Sound` is not a separate export | Access via `CometChatSoundManager.Sound`, not `import { Sound }` | *** ## Events | Symptom | Cause | Fix | | - | - | - | | Event listener not firing | Subscribed to wrong event name | Check the [Events](/ui-kit/react/v6/events) page for exact event names | | Duplicate event triggers | Multiple subscriptions without cleanup | Unsubscribe in `useEffect` cleanup or component unmount | | Event fires but UI doesn't update | State not updated in event handler | Ensure you call `setState` or equivalent in the handler | This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.