I am having the same problem. Implemented the MongoDB fully within the editor but when I builded the project to iOS it didn’t work. it returned this error:
NotSupportedException: ./External/il2cpp/builds/libil2cpp/icalls/mscorlib/System.Reflection/Module.cpp(112) : Unsupported internal call for IL2CPP:Module::GetPEKind - “This icall is not supported by il2cpp.”