Here is the fix
- Go to directory cd /usr/share/fonts/truetype/freefont/
- Delete both the FreeSerif.ttf and FreeSans.ttf file.
Command
sudo rm -f /usr/share/fonts/truetype/freefont/FreeSerif.ttf
sudo rm -f /usr/share/fonts/truetype/freefont/FreeSans.ttf
Then restart your browser.