You'll need to upgrade your Mac to macOS Mojave and you'll be able to view models with AR Quick Look in (desktop) Safari.
About the message you're getting (I assume on iOS since it mentions "Mobile"), one possibility is that the model is too large for the memory available to AR Quick Look on iOS. See https://developer.apple.com/videos/play/wwdc2018-603/?time=2166 for details.
Hi thanks for responding.
Its very unlikely that my model is too large its only 810Kb, whereas the other models for the ARgallery that i have on my site are 10MB....
There must be some other incopatibility but there seems to be no way i can get any informational message as to why its not rendered.
The .usdz file passed the usdcheker compliance tests....
Is there anything else i can do to find why tis not rendering? I opened the usdz file all textures seem to be there..