It could be, that your app isn’t whitelisted. Here’s the documentation: https://github.com/EpicGames/UnrealEngine/blob/4.14/Engine/Plugins/Runtime/Nvidia/Ansel/ThirdParty/NVAnselSDK/docs/Ansel_integration_guide.md
It could be, that your app isn’t whitelisted. Here’s the documentation: https://github.com/EpicGames/UnrealEngine/blob/4.14/Engine/Plugins/Runtime/Nvidia/Ansel/ThirdParty/NVAnselSDK/docs/Ansel_integration_guide.md