Have been encountering this error when trying to launch my project on my Snapdragon 820 phone:
Program.Main: ERROR: AutomationTool terminated with exception: System.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary.
LogPlayLevel: at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
LogPlayLevel: at UnrealBuildTool.UnrealPluginLanguage.ProcessPluginNode(String Architecture, String NodeName, String Input, XDocument& XMLWork)
LogPlayLevel: at UnrealBuildTool.UnrealPluginLanguage.ProcessPluginNode(String Architecture, String NodeName, String Input)
LogPlayLevel: at UnrealBuildTool.UnrealPluginLanguage.Init(List`1 Architectures, Boolean bDistribution, String EngineDirectory, String BuildDirectory, String ProjectDirectory)
LogPlayLevel: at UnrealBuildTool.UEDeployAndroid.MakeApk(AndroidToolChain ToolChain, String ProjectName, String ProjectDirectory, String OutputPath, String EngineDirectory, Boolean bForDistribution, String CookFlavor, Boolean bMakeSeparateApks, Boolean bIncrementalPackage, Boolean bDisallowPackagingDataInApk, Boolean bDisallowExternalFilesDir)
LogPlayLevel: at UnrealBuildTool.UEDeployAndroid.PrepForUATPackageOrDeploy(FileReference ProjectFile, String ProjectName, String ProjectDirectory, String ExecutablePath, String EngineDirectory, Boolean bForDistribution, String CookFlavor, Boolean bIsDataDeploy)
LogPlayLevel: at AndroidPlatform.Deploy(ProjectParams Params, DeploymentContext SC)
LogPlayLevel: at Project.Deploy(ProjectParams Params)
LogPlayLevel: at BuildCookRun.DoBuildCookRun(ProjectParams Params)
LogPlayLevel: at BuildCookRun.ExecuteBuild()
LogPlayLevel: at AutomationTool.BuildCommand.Execute()
LogPlayLevel: at AutomationTool.Automation.Execute(List`1 CommandsToExecute, CaselessDictionary`1 Commands)
LogPlayLevel: at AutomationTool.Automation.Process(String[] Arguments)
LogPlayLevel: at AutomationTool.Program.MainProc(Object Param)
LogPlayLevel: at AutomationTool.InternalUtils.RunSingleInstance(Func`2 Main, Object Param)
LogPlayLevel: at AutomationTool.Program.Main()
LogPlayLevel: Program.Main: AutomationTool exiting with ExitCode=1 (Error_Unknown)