Please paste the results of the following commands:
/usr/bin/xdg-mime query default application/pdf /usr/lib/chromium-browser/xdg-mime query default application/pdf
(both should return the desktop file of your preferred pdf viewer)
if it's ok, maybe the mime type is wrong:
try:
xdg-mime query filetype /name/of/one/of/your.pdf
it should say "application/pdf"
Please paste the results of the following commands:
/usr/bin/xdg-mime query default application/pdf chromium- browser/ xdg-mime query default application/pdf
/usr/lib/
(both should return the desktop file of your preferred pdf viewer)
if it's ok, maybe the mime type is wrong:
try:
xdg-mime query filetype /name/of/ one/of/ your.pdf
it should say "application/pdf"