Problem with source/pdf

Just signed up for pro, on Chromebook using Remnote through Chrome browser.

1 - using clipper, create a new rem from pdf. “Source” shows pdf URL. I take some notes and close Remnote
2 - re-open the rem for the pdf, and Source is “unnamed”. Clicking on it opens new pane with message “loading pdf” with perpetually spinning wheel. PDF never loads.
3 - I paste in the correct pdf URL, but it reverts to unnamed
4- Started a new, blank document and pasted the URL for pdf - again turned to “unnamed” and would not load.
This is the pdf: https://www.neurotossinabotulinica.it/wpdata2018/wp-content/uploads/2018/12/Dystonia_diagnosis-and-management.pdf


I think…
1 - “Source” shows pdf URL is the Right Window Pane
2 - Source is “unnamed” is a Document whose Source is a reference to the PDF (Left Window Pane)