Git https ssh errors

I get the error in Linux when trying to git push:
error: The requested URL returned error: 403 Forbidden while accessing https://github.com/avulanov/ann-benchmark.git/info/refs
When I set:
git remote set-url origin https://username@github.com/username/reponame.git
I get:
Gtk-WARNING **: cannot open display:
The following command fixes it:
unset SSH_ASKPASS
http://stackoverflow.com/questions/16077971/git-push-produces-gtk-warning