Export libgdx project to HTML - did you forget to inherit a required module?

I try to export my libgdx game in HTML. I already export it on Android and desktop, and it works well. But when I execute ./gradlew html:dist, I have many errors like this one:

[ERROR] Line 75: No source code is available for type net.spookygames.gdx.gameservices.playtomic.PlaytomicServicesHandler; did you forget to inherit a required module?

net.spookygames.gdx.gameservices is a package which is next to my main package in core folder:

I saw on documentation and on another question that I need use reflection by putting this line in my GdxDefinition.gwt.xml in html folder:

<extend-configuration-property name="gdx.reflect.include" value="net.spookygames.gdx.gameservices" />

But it didn't change anything.. Do I need to do something else? Thanks