Often time I come across the type3 font type error when submitting papers to scientific conference. What it means is that you have a non-standard font in your PDF.
For the written text part, just put the following in the preamble of your .tex file and show it fine.
\pdfminorversion=4
Another nasty place that these fonts turn up is in your plots. Especially the one using vector graphics. If using matplot (Python) for your plot, just put the following after your import and it fixes the problem.
import matplotlib.pyplot as plt