Certain online submission services check the fonts used in the submitted PDF file. Many of them allow only Type 1 and TrueType fonts in the PDF. Type 3 fonts which may not scale well in printing are not allowed. I got the error shown in the screenshot above when I tried submitting to one such website.
- Find out which fonts are being used in your PDF and for what objects. This can be done by using the PDFFonts tool as described here.
For example, I found that I had been using Type 3 fonts in a SVG image and in a plot generated by Matplotlib.
Next fix the source of these font problems. I edited the SVG image to use Type 1 or TrueType fonts. I requested Matplotlib to use LaTeX fonts for text rendering, as described here.
The PDF file regenerated from these files passed the font checks🙂
Tried with: Ubuntu 14.04