*moved as the Arcade is a 'Website Issue' that is generally dealt with by Tom.
What version of C2 are you using?
Are you using the Arcade Export option? (need to ask, just in case)
Have you checked the error console for errors?
If it doesn't work with the latest C2, then you could try sending the Arcade exported .zip file to with as much detail as you can - versions/plugins/system etc - and hopefully someone will be able to investigate.