While my application is starting I got an error

[normidar]

it is this:
Launching lib/main.dart on Android SDK built for x86 in debug mode...
D8: Cannot fit requested classes in a single dex file (# methods: 73470 > 65536)
com.android.builder.dexing.DexArchiveMergerException: Error while merging dex archives:
The number of method references in a .dex file cannot exceed 64K.
Learn how to resolve this issue at https://developer.android.com/tools/building/multidex.html
at com.android.builder.dexing.D8DexArchiveMerger.getExceptionToRethrow(D8DexArchiveMerger.java:131)
at com.android.builder.dexing.D8DexArchiveMerger.mergeDexArchives(D8DexArchiveMerger.java:118)
at com.android.build.gradle.internal.transforms.DexMergerTransformCallable.call(DexMergerTransformCallable.java:102)
at com.android.build.gradle.internal.tasks.DexMergingTaskRunnable.run(DexMergingTask.kt:444)
at com.android.build.gradle.internal.tasks.Workers$ActionFacade.run(Workers.kt:335)
at org.gradle.workers.internal.AdapterWorkAction.execute(AdapterWorkAction.java:50)
at org.gradle.workers.internal.DefaultWorkerServer.execute(DefaultWorkerServer.java:47)
at org.gradle.workers.internal.NoIsolationWorkerFactory$1$1$1.create(NoIsolationWorkerFactory.java:65)
at org.gradle.workers.internal.NoIsolationWorkerFactory$1$1$1.create(NoIsolationWorkerFactory.java:61)
at org.gradle.internal.classloader.ClassLoaderUtils.executeInClassloader(ClassLoaderUtils.java:98)
at org.gradle.workers.internal.NoIsolationWorkerFactory$1$1.execute(NoIsolationWorkerFactory.java:61)
at org.gradle.workers.internal.AbstractWorker$1.call(AbstractWorker.java:44)
at org.gradle.workers.internal.AbstractWorker$1.call(AbstractWorker.java:41)
at org.gradle.internal.operations.DefaultBuildOperationExecutor$CallableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:416)
at org.gradle.internal.operations.DefaultBuildOperationExecutor$CallableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:406)
at org.gradle.internal.operations.DefaultBuildOperationExecutor$1.execute(DefaultBuildOperationExecutor.java:165)
at org.gradle.internal.operations.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:250)
at org.gradle.internal.operations.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:158)
at org.gradle.internal.operations.DefaultBuildOperationExecutor.call(DefaultBuildOperationExecutor.java:102)
at org.gradle.internal.operations.DelegatingBuildOperationExecutor.call(DelegatingBuildOperationExecutor.java:36)
at org.gradle.workers.internal.AbstractWorker.executeWrappedInBuildOperation(AbstractWorker.java:41)
at org.gradle.workers.internal.NoIsolationWorkerFactory$1.execute(NoIsolationWorkerFactory.java:56)
at org.gradle.workers.internal.DefaultWorkerExecutor$3.call(DefaultWorkerExecutor.java:215)
at org.gradle.workers.internal.DefaultWorkerExecutor$3.call(DefaultWorkerExecutor.java:210)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at org.gradle.internal.work.DefaultConditionalExecutionQueue$ExecutionRunner.runExecution(DefaultConditionalExecutionQueue.java:215)
at org.gradle.internal.work.DefaultConditionalExecutionQueue$ExecutionRunner.runBatch(DefaultConditionalExecutionQueue.java:164)
at org.gradle.internal.work.DefaultConditionalExecutionQueue$ExecutionRunner.run(DefaultConditionalExecutionQueue.java:131)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:64)
at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:48)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:56)
at java.lang.Thread.run(Thread.java:748)
Caused by: com.android.tools.r8.CompilationFailedException: Compilation failed to complete
at com.android.tools.r8.utils.t.a(:55)
at com.android.tools.r8.D8.run(:11)
at com.android.builder.dexing.D8DexArchiveMerger.mergeDexArchives(D8DexArchiveMerger.java:116)
... 34 more
Caused by: com.android.tools.r8.utils.AbortException: Error: null, Cannot fit requested classes in a single dex file (# methods: 73470 > 65536)
at com.android.tools.r8.utils.Reporter.a(:21)
at com.android.tools.r8.utils.Reporter.a(:7)
at com.android.tools.r8.dex.VirtualFile.a(:33)
at com.android.tools.r8.dex.VirtualFile$h.a(:5)
at com.android.tools.r8.dex.ApplicationWriter.a(:13)
at com.android.tools.r8.dex.ApplicationWriter.write(:35)
at com.android.tools.r8.D8.d(:44)
at com.android.tools.r8.D8.b(:1)
at com.android.tools.r8.utils.t.a(:23)
... 36 more

FAILURE: Build failed with an exception.

• What went wrong:
  Execution failed for task ':app:mergeDexDebug'.

A failure occurred while executing com.android.build.gradle.internal.tasks.Workers$ActionFacade
com.android.builder.dexing.DexArchiveMergerException: Error while merging dex archives:
The number of method references in a .dex file cannot exceed 64K.
Learn how to resolve this issue at https://developer.android.com/tools/building/multidex.html

• Try:
  Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

• Get more help at https://help.gradle.org
  BUILD FAILED in 1m 4s
  [!] The shrinker may have failed to optimize the Java bytecode.
  To disable the shrinker, pass the --no-shrink flag to this command.
  To learn more, see: https://developer.android.com/studio/build/shrink-code
  Exception: Gradle task assembleDebug failed with exit code 1
  Exited (sigterm)

[normidar]

when I remove the firebase_ui, it is returned to well

[arma7x]

edit your android/app/build.gradle and add minifyEnabled true

buildTypes {
        release {
            // TODO: Add your own signing config for the release build.
            // Signing with the debug keys for now, so `flutter run --release` works.
            signingConfig signingConfigs.debug
            minifyEnabled true
        }
        debug{
            minifyEnabled true
        }
    }