error CS0246: namespace HostData & MasterServerEvent could not be found when making a build in WebGL

Made a build for PC, Mac Linux and worked fine, however, when I make a build on WebGL I get the error CS0246 messages saying:

The type or namespace name 'HostData' could not be found
The type or namespace name 'MasterServerEvent' could not be found

Is there any way to resolve this or would I have to code it differently for WebGL or how do I resolve this?