Recently I uploaded a LaTeX generated PDF to an educational site which uses an internal PDF viewer (crocodoc). However, when displayed, many letters where missing. As far as I can tell it is mostly letters "f" that is missing.
In my preamble I wrote the following code:
\documentclass[11pt,a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage{fullpage}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage[linktoc=none]{hyperref}
\usepackage{caption}
\usepackage{subcaption}
\usepackage{amsmath,amssymb,bm, accents}
\usepackage{pgfplots}
\usepackage{parskip}
Any idea what might cause this display error?