Can't open external links in gtk applications

I can’t open the links in the browser when there is a link in gtk applications.

Step to treproduce:

  1. open a gtk3 or gtk2 application ( for example pamac, liferea and lxtask in my case)
  2. open a link (for example the source of a feed or the official site’s application or the lxde site in the help–about menu of lxtasks) in the external browser by clicking on it.
  3. it will be opened a new, blank browser instance instead the link

The problem doesn’t occurs with qt applications (in my case , vlc )