I encountered an error while uploading the Unity version ( 2019.4.30f1 -> 2021.3.1f1 )

hello. Our project was building and servicing the app using "unity 2019.4.30f1". Our project is about to upgrade to "unity 2021.3.1f1". Unfortunately, we encountered the following error while building ios. I would like your help to solve it. Thank you.

 Exception: Failed running /Applications/Unity/Hub/Editor/2021.3.1f1/Unity.app/Contents/il2cpp/build/deploy/UnityLinker @"/Volumes/T7-SSD/svn/unity-proj/Temp/StagingArea/Data/Managed/response.rsp"
 
 stdout:
 Fatal error in Unity CIL Linker
 Mono.Linker.LinkerFatalErrorException: ILLink: error IL1005: System.Windows.Forms.Control.get_Font(): Error processing method 'System.Windows.Forms.Control.get_Font()' in assembly 'System.Windows.Forms.dll'
  ---> System.NullReferenceException: Object reference not set to an instance of an object.
    at Mono.Linker.Steps.MarkStep.MarkMarshalSpec(IMarshalInfoProvider spec, DependencyInfo& reason, IMemberDefinition sourceLocationMember) in /Users/bokken/build/output/unity/il2cpp/repos/monolinker/src/linker/Linker.Steps/MarkStep.cs:line 565
    at Mono.Linker.Steps.MarkStep.ProcessMethod(MethodDefinition method, DependencyInfo& reason) in /Users/bokken/build/output/unity/il2cpp/repos/monolinker/src/linker/Linker.Steps/MarkStep.cs:line 2423
    at Unity.Linker.Steps.UnityMarkStep.ProcessMethod(MethodDefinition method, DependencyInfo& reason) in /Users/bokken/build/output/unity/il2cpp/UnityLinker/Linker.Steps/UnityMarkStep.cs:line 222
    at Mono.Linker.Steps.MarkStep.ProcessQueue() in /Users/bokken/build/output/unity/il2cpp/repos/monolinker/src/linker/Linker.Steps/MarkStep.cs:line 391
    --- End of inner exception stack trace ---
    at Mono.Linker.Steps.MarkStep.ProcessQueue() in /Users/bokken/build/output/unity/il2cpp/repos/monolinker/src/linker/Linker.Steps/MarkStep.cs:line 393
    at Mono.Linker.Steps.MarkStep.ProcessPrimaryQueue() in /Users/bokken/build/output/unity/il2cpp/repos/monolinker/src/linker/Linker.Steps/MarkStep.cs:line 376
    at Mono.Linker.Steps.MarkStep.Process()
    at Unity.Linker.Steps.UnityMarkStep.Process(LinkContext context) in /Users/bokken/build/output/unity/il2cpp/UnityLinker/Linker.Steps/UnityMarkStep.cs:line 255
    at Unity.Linker.UnityPipeline.ProcessStep(LinkContext context, IStep step) in /Users/bokken/build/output/unity/il2cpp/UnityLinker/Linker/UnityPipeline.cs:line 23
    at Mono.Linker.Pipeline.Process(LinkContext context) in /Users/bokken/build/output/unity/il2cpp/repos/monolinker/src/linker/Linker/Pipeline.cs:line 128
    at Unity.Linker.UnityDriver.UnityRun(Boolean noProfilerAllowed, ILogger customLogger) in /Users/bokken/build/output/unity/il2cpp/UnityLinker/Linker/UnityDriver.cs:line 124
    at Unity.Linker.UnityDriver.RunDriverWithoutErrorHandling(ILogger customLogger, Boolean noProfilerAllowed) in /Users/bokken/build/output/unity/il2cpp/UnityLinker/Linker/UnityDriver.cs:line 80
    at Unity.Linker.UnityDriver.RunDriver() in /Users/bokken/build/output/unity/il2cpp/UnityLinker/Linker/UnityDriver.cs:line 61
 stderr:
 
 UnityEditorInternal.Runner.RunProgram (UnityEditor.Utils.Program p, System.String exe, System.String args, System.String workingDirectory, UnityEditor.Scripting.Compilers.CompilerOutputParserBase parser) (at /Users/bokken/buildslave/unity/build/Editor/Mono/BuildPipeline/BuildUtils.cs:133)
 UnityEditorInternal.Runner.RunNetCoreProgram (System.String exe, System.String args, System.String workingDirectory, UnityEditor.Scripting.Compilers.CompilerOutputParserBase parser, System.Action`1[T] setupStartInfo) (at /Users/bokken/buildslave/unity/build/Editor/Mono/BuildPipeline/BuildUtils.cs:91)
 UnityEditorInternal.AssemblyStripper.RunAssemblyLinker (System.Collections.Generic.IEnumerable`1[T] args, System.String& out, System.String& err, System.String linkerPath, System.String workingDirectory) (at /Users/bokken/buildslave/unity/build/Editor/Mono/BuildPipeline/AssemblyStripper.cs:156)
 UnityEditorInternal.AssemblyStripper.StripAssembliesTo (System.String outputFolder, System.String& output, System.String& error, System.Collections.Generic.IEnumerable`1[T] linkXmlFiles, UnityEditorInternal.UnityLinkerRunInformation runInformation) (at /Users/bokken/buildslave/unity/build/Editor/Mono/BuildPipeline/AssemblyStripper.cs:147)
 UnityEditorInternal.AssemblyStripper.RunAssemblyStripper (UnityEditorInternal.UnityLinkerRunInformation runInformation) (at /Users/bokken/buildslave/unity/build/Editor/Mono/BuildPipeline/AssemblyStripper.cs:233)
 UnityEditorInternal.AssemblyStripper.StripAssemblies (System.String managedAssemblyFolderPath, UnityEditorInternal.BaseUnityLinkerPlatformProvider unityLinkerPlatformProvider, UnityEditorInternal.IIl2CppPlatformProvider il2cppPlatformProvider, UnityEditor.RuntimeClassRegistry rcr, UnityEditor.ManagedStrippingLevel managedStrippingLevel) (at /Users/bokken/buildslave/unity/build/Editor/Mono/BuildPipeline/AssemblyStripper.cs:168)
 UnityEditorInternal.IL2CPPBuilder.Run () (at /Users/bokken/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:616)
 UnityEditorInternal.IL2CPPUtils.RunIl2Cpp (System.String tempFolder, System.String stagingAreaData, UnityEditorInternal.IIl2CppPlatformProvider platformProvider, System.Action`1[T] modifyOutputBeforeCompile, UnityEditor.RuntimeClassRegistry runtimeClassRegistry) (at /Users/bokken/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:278)
 UnityEditor.iOS.PostProcessiPhonePlayer.CrossCompileManagedDlls (UnityEditor.iOS.PostProcessiPhonePlayer+BuildSettings bs, UnityEditor.iOS.PostProcessiPhonePlayer+ProjectPaths paths, UnityEditor.AssemblyReferenceChecker checker, UnityEditor.RuntimeClassRegistry usedClassRegistry, UnityEditor.Build.Reporting.BuildReport buildReport) (at /Users/bokken/buildslave/unity/build/PlatformDependent/iPhonePlayer/Extensions/Common/BuildPostProcessor.cs:932)
 UnityEditor.iOS.PostProcessiPhonePlayer.PostProcess (UnityEditor.iOS.PostProcessiPhonePlayer+BuildSettings bs, UnityEditor.iOS.PostProcessiPhonePlayer+ProjectPaths paths, UnityEditor.RuntimeClassRegistry usedClassRegistry, UnityEditor.Build.Reporting.BuildReport buildReport) (at /Users/bokken/buildslave/unity/build/PlatformDependent/iPhonePlayer/Extensions/Common/BuildPostProcessor.cs:755)
 UnityEditor.iOS.PostProcessiPhonePlayer.PostProcess (UnityEditor.iOS.PostProcessorSettings postProcessorSettings, UnityEditor.Modules.BuildPostProcessArgs args) (at /Users/bokken/buildslave/unity/build/PlatformDependent/iPhonePlayer/Extensions/Common/BuildPostProcessor.cs:695)
 UnityEditor.iOS.iOSBuildPostprocessor.PostProcess (UnityEditor.Modules.BuildPostProcessArgs args) (at /Users/bokken/buildslave/unity/build/PlatformDependent/iPhonePlayer/Extensions/Common/ExtensionModule.cs:45)
 Rethrow as BuildFailedException: Exception of type 'UnityEditor.Build.BuildFailedException' was thrown.
 UnityEditor.iOS.iOSBuildPostprocessor.PostProcess (UnityEditor.Modules.BuildPostProcessArgs args) (at /Users/bokken/buildslave/unity/build/PlatformDependent/iPhonePlayer/Extensions/Common/ExtensionModule.cs:49)
 UnityEditor.Modules.DefaultBuildPostprocessor.PostProcess (UnityEditor.Modules.BuildPostProcessArgs args, UnityEditor.BuildProperties& outProperties) (at /Users/bokken/buildslave/unity/build/Editor/Mono/Modules/DefaultBuildPostprocessor.cs:28)
 UnityEditor.PostprocessBuildPlayer.Postprocess (UnityEditor.BuildTargetGroup targetGroup, UnityEditor.BuildTarget target, System.Int32 subtarget, System.String installPath, System.String companyName, System.String productName, System.Int32 width, System.Int32 height, UnityEditor.BuildOptions options, UnityEditor.RuntimeClassRegistry usedClassRegistry, UnityEditor.Build.Reporting.BuildReport report) (at /Users/bokken/buildslave/unity/build/Editor/Mono/BuildPipeline/PostprocessBuildPlayer.cs:370)
 UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr, Boolean&) (at /Users/bokken/buildslave/unity/build/Modules/IMGUI/GUIUtility.cs:189)