Apparently the URL is case sensitive. I changed upper case to lower case and got 7 pages. But the graphic with the map of Africa does not seem to be included.
https://www.medrxiv.org/content/10.1101/2021.03.26.21254377v1.full.pdf
And if, at the end “.full.pdf” is replaced with “.full-text” then there’s this...
https://www.medrxiv.org/content/10.1101/2021.03.26.21254377v1.full-text
Yeah, I was afraid of that. I had my caps lock key on when I typed in the link.
I don’t see the graphic though. Is there a link to it in the article? I didn’t see one.