3D FlipBook - Not working without login showing Invalid top-level pages dictionary

Hello team,

I have installed this plugin on my site. When I am logged in, I can see the pdf in book format http://prntscr.com/10jmxkh. But without login it's showing http://prntscr.com/10jmxzm.

My site is https://smallbusinessassociation.com.au/staging

Also sometimes not able to see thumbnail. Please help me ASAP.

Thanks