It is a wifi connection with no proxy... I supposing that I removed all proxy configs, and Firefox is working fine. But any terminal command line not works:
curl --verbose http://w3c.orgsay (5) Could not resolve proxy: http.
wget http://w3c.orgsay failed: Name or service not known. wget: unable to resolve host address ‘http’.
About wget error, I tested this change
resolv.conf suggestion but no effect.
changing URL to
https://w3c.orgthe error messages not changes (say "http").
I am using UBUNTU 18 LTS.
sudo apt updateis working (!).