Any idea as to why my PDFs are not being loaded in Zoho Notebooks??

It shows the following screenshot below when I try to add the PDF in from the Chrome Extension.

Even after showing the "Failed to add PDF file!" above, the note is loaded into my notebook, but it's completely blank??

I've tried deleting the Chrome Extension and re-loading, but it's still not working?? It doesn't even work when I drag and drop a PDF as well?? It's just completely blank with 3 dots like below?? Any ideas?