iOS Unity Build Error : "does not refer to a file in a known build section"

This error occurred and I cannot build.

 Exception: The given path Libraries/Plugins/iOS/GADURewardedInterstitialAd.h does not refer to a file in a known build section
 UnityEditor.iOS.Xcode.PBXProjectData.BuildSectionAny (UnityEditor.iOS.Xcode.PBX.PBXNativeTargetData target, System.String path, System.Boolean isFolderRef) (at /Users/bokken/buildslave/unity/build/External/XcodeAPI/Xcode/PBXProjectData.cs:250)
 UnityEditor.iOS.Xcode.PBXProject.BuildSectionAny (UnityEditor.iOS.Xcode.PBX.PBXNativeTargetData target, System.String path, System.Boolean isFolderRef) (at /Users/bokken/buildslave/unity/build/External/XcodeAPI/Xcode/PBXProject.cs:86)
 UnityEditor.iOS.Xcode.PBXProject.AddBuildFileImpl (System.String targetGuid, System.String fileGuid, System.Boolean weak, System.String compileFlags) (at /Users/bokken/buildslave/unity/build/External/XcodeAPI/Xcode/PBXProject.cs:266)
 UnityEditor.iOS.Xcode.PBXProject.AddFileToBuildWithFlags (System.String targetGuid, System.String fileGuid, System.String compileFlags) (at /Users/bokken/buildslave/unity/build/External/XcodeAPI/Xcode/PBXProject.cs:295)
 UnityEditor.iOS.PostProcessiPhonePlayer.BuildXCodeProject (UnityEditor.iOS.PostProcessiPhonePlayer+ProjectPaths paths, UnityEditor.iOS.PostProcessiPhonePlayer+BuildSettings bs, UnityEditor.iOS.PostProcessiPhonePlayer+UsedFeatures usedFeatures, UnityEditor.iOS.PostProcessiPhonePlayer+IncludedFileList includedFiles, System.Collections.Generic.List`1[T] frameworks, System.Collections.Generic.List`1[T] initialInstallTags) (at /Users/bokken/buildslave/unity/build/PlatformDependent/iPhonePlayer/Extensions/Common/BuildPostProcessor.cs:2555)
 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:808)
 UnityEditor.iOS.PostProcessiPhonePlayer.PostProcess (UnityEditor.iOS.PostProcessorSettings postProcessorSettings, UnityEditor.Modules.BuildPostProcessArgs args) (at /Users/bokken/buildslave/unity/build/PlatformDependent/iPhonePlayer/Extensions/Common/BuildPostProcessor.cs:663)
 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:29)
 UnityEditor.PostprocessBuildPlayer.Postprocess (UnityEditor.BuildTargetGroup targetGroup, UnityEditor.BuildTarget target, 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:337)
 UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr, Boolean&) (at /Users/bokken/buildslave/unity/build/Modules/IMGUI/GUIUtility.cs:189)

It works normally during the first build, but the error occurs from the second build.

If you delete the build folder, it will be successful. What should I try?

Help me ... T_T