LogAximmetry: Error: Plugin installer: C:/Program Files/Epic Games/UE_4.26/Engine/Plugins/Marketplace/Smartsuit/Source/Smartsuit/Public/SmartsuitBlueprintLibrary.h(65) : LogCompile: Error: An explicit Category specifier is required for Blueprint accessible functions in an Engine module.
LogAximmetry: Error: Plugin installer: C:/Program Files/Epic Games/UE_4.26/Engine/Plugins/Marketplace/Smartsuit/Source/Smartsuit/Public/SmartsuitBlueprintLibrary.h(68) : LogCompile: Error: An explicit Category specifier is required for Blueprint accessible functions in an Engine module.
LogAximmetry: Error: Plugin installer: Error: Smartsuit could not be built. UnrealBuildTool exited with 6.
i fix the problem .
here's sloution first modify 'Plugins/Smartsuit/Source/Smartsuit/Public/SmartsuitBlueprintLibrary.h " like https://github.com/Rokoko/rokoko-studio-live-unreal-engine/pull/24/files
then make sure in your "UnrealEngine-4.26.1-release\Engine\Source\ThirdParty\Eigen" get all eigen headers there it will be ok
GoodLuck