If you're using the [community layouts feature](https://docs.qmk.fm/#/feature_layouts) and using the 60_ansi layout, you need to make sure that you include this on your config.h to ensure that the RGB Matrix is properly configured:
See [build environment setup](https://docs.qmk.fm/build_environment_setup.html) then the [make instructions](https://docs.qmk.fm/make_instructions.html) for more information.