This took me a very long time to figure out. I had the same issue.

Specifically in macOS the emacs shell does not properly inherit the PATH. In my situation, this meant that biber was not in path, but latexmk was. latexmk just builds the pdf anyway, with no viewable error message anywhere except ‘empty bibliography’ or ‘unknown citation’. There are many better solutions in the linked post, but here is my janky one solution:

(setq org-latex-pdf-process '("export PATH=\"/Library/TeX/texbin/:$PATH\"; latexmk -f -pdf -%latex -interaction=nonstopmode -output-directory=%o %f"))

This took me a very long time to figure out. I had the same issue.

Specifically in macOS the emacs shell does not properly inherit the PATH. In my situation, this meant that biber was not in path, but latexmk was. latexmk just builds the pdf anyway, with no viewable error message anywhere except ‘empty bibliography’ or ‘unknown citation’. There are many better solutions in the linked post, but here is my janky one solution:

 (setq org-latex-pdf-process '("export PATH=\"/Library/TeX/texbin/:$PATH\";latexmk -f -pdf -%latex -interaction=nonstopmode -output-directory=%o %f"))