C++ plugins failed to launch/build on android

Hi everybody!
I buy a plugin with in it 2 C++ class. One is BP_gravitycharacter and charactergravitymovement.
I create a BP child (in Blueprint not in C++) of BP_gravitycharacter and this work in the viewport.
But i have a little problem, when i want to launch it on mobile (android or iOS) (or build the apk), the build don’t work, i have this problem :
Could not find SuperStruct GravityCharacter to create BP_GravityCharacter_C

I think he can’t check the C++ code of the plugin to create the BP_GravityCharacterChild.
Can you know a solution?

Thanks a lot!