The answer is in the very first post on this topic. The issue is in the host DAW and not SpectraLayers. You have the processing precision of VST plugins set to the non-default “64 bit float”.
This forum already contained a post with a title that exactly describes the issue, including the workaround:
NO SOUND - Spectralayers Pro 6 in Cubase pro 10.0.30
In Cubase 10, menu Studio → Studio setup → VST Audio System → Processing precision → set this to “32 bit float”.