this error appear when i run the code

Error: Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: undefined. You likely forgot to export your component from the file it's defined in, or you might have mixed up default and named imports.
Check the render method of `App`.

This error is located at:
in App (created by ExpoRoot)
in ExpoRoot (at renderApplication.js:45)
in RCTView (at View.js:34)
in View (at AppContainer.js:106)
in DevAppContainer (at AppContainer.js:121)
in RCTView (at View.js:34)
in View (at AppContainer.js:132)
in AppContainer (at renderApplication.js:39)
- node_modules/react-native/Libraries/LogBox/LogBox.js:148:8 in registerError
- node_modules/react-native/Libraries/LogBox/LogBox.js:59:8 in errorImpl
- node_modules/react-native/Libraries/LogBox/LogBox.js:33:4 in console.error
- node_modules/expo/build/environment/react-native-logs.fx.js:27:4 in error
- node_modules/react-native/Libraries/Core/ExceptionsManager.js:104:6 in reportException
- node_modules/react-native/Libraries/Core/ExceptionsManager.js:171:19 in handleException
- node_modules/react-native/Libraries/Core/setUpErrorHandling.js:24:6 in handleError
- node_modules/expo-error-recovery/build/ErrorRecovery.fx.js:9:32 in ErrorUtils.setGlobalHandler$argument_0
- node_modules/regenerator-runtime/runtime.js:63:36 in tryCatch
- node_modules/regenerator-runtime/runtime.js:293:29 in invoke
- node_modules/regenerator-runtime/runtime.js:63:36 in tryCatch
- node_modules/regenerator-runtime/runtime.js:154:27 in invoke
- node_modules/regenerator-runtime/runtime.js:164:18 in PromiseImpl.resolve.then$argument_0
- node_modules/react-native/node_modules/promise/setimmediate/core.js:37:13 in tryCallOne
- node_modules/react-native/node_modules/promise/setimmediate/core.js:123:24 in setImmediate$argument_0
- node_modules/react-native/Libraries/Core/Timers/JSTimers.js:130:14 in _callTimer
- node_modules/react-native/Libraries/Core/Timers/JSTimers.js:181:14 in _callImmediatesPass
- node_modules/react-native/Libraries/Core/Timers/JSTimers.js:441:30 in callImmediates
- node_modules/react-native/Libraries/BatchedBridge/MessageQueue.js:387:6 in __callImmediates
- node_modules/react-native/Libraries/BatchedBridge/MessageQueue.js:135:6 in __guard$argument_0
- node_modules/react-native/Libraries/BatchedBridge/MessageQueue.js:364:10 in __guard
- node_modules/react-native/Libraries/BatchedBridge/MessageQueue.js:134:4 in flushedQueue
* [native code]:null in flushedQueue
* [native code]:null in invokeCallbackAndReturnFlushedQueue