Sharing OnlyOffice document files to others causes login dialog to appear?

I was sharing a .docx file to someone else, but when I checked out the link to edit the file through OnlyOffice, a login prompt keeps nagging me repetitively. The document is still editable though aside from the numerous login prompts. I’m also finding that it appears even if I am logged into my NextCloud instance. Anyone know why the prompts keep appearing?