Internet connection is working.
apt-get is working.
Trying to add ppa:cooperjona/lightread
but an error has raised:
Cannot add PPA 'ppa:cooperjona/lightread' . Please check that the PPA name or format is correct.
I supposed there is an error in writing or in the PPA.
I tried also the 'ppa:tombeckmann/ppa' but with same error.
Open Terminal and run the command:
sudo apt-get install --reinstall ca-certificates
It may work, but if doesn't then run:
sudo -E add-apt-repository ppa:ppaname/ppa
Instead of:
sudo add-apt-repository ppa:ppaname/ppa
I googled the error and find this. So i tried to clone a git as he did there and has the same result.
So to solve this:
and things become smooth again :)
I had this exact error message about checking the PPA name or format. My network was connected and I could ping websites and browse fine.
What I finally figured out was the clock on my computer was set wrong. If it's off more than a small amount, the secure connection will fail and it will report this message. It's very unhelpful.
Check your clock. I set mine and then it immediately worked as expected.