Unauthorized use of Caching API in webplayer

Hi everyone, im trying to download some assetbundles from server into my webplayer game. Bud i dont know why, but in editor download working, when i build my project and upload to my server, and run it from server donwload doesnt work. and console write me error: Unauthorized use of Caching API or something like that.

Anybody knows how to fix it? Thanks