Hi, I also sometimes see a blank frame in place of the document. I have to refresh several attempts and then do see the pdf doc. I am also using cloudflare but this happens even if i turn on bypass of cloudflare. It also happens in the POST wordpress editor sometimes where a previously embedded doc is blank. There is a setting in Embed for CACHE and I have to toggle it for the embedded page to appear in the editor. This may have sometime to do with the live view where the docs are also blank. I have tried both settings of CACHE in the plugin but they appear to behave the same???
