Sometimes, when you write a paper using Latex, and you submit to some conference, such as IEEE's for example, you might encounter this error, or some of its variants:
fonttype: Upload failed: Font DejaVuSans is of type Type 3
This is usually due to the fact that some of your figures in the paper uses Type 3 font, which needs to be changed. See here for more information: http://phyletica.org/matplotlib-fonts/
In order to fix this, you first need to find the PDF figures responsible. This can be done as follows:
apt install poppler-utils
pdffonts figure1.pdf
But for cases when you have too many figures, this might take some time. Here is the script, called checktype3.sh, which will do it for all PDF files in the current directory.
chmod +x checktype3.sh
./checktype3.sh
Look for "Type 3" in the output, and redraw the files accordingly.
Tested on Ubuntu 22.04.