I'm having an odd error while I'm trying to upgrade requirements.txt packages in Pycharm 2016.3.1.
Everything was ok until 10 minutes ago...
If I click on upgrade any library I get the next error.
Error occurred. Please, check your internet connection.
I don't know what to do, I re-create the virtualenv with no luck.
The same thing happened to me. Please check your requirements.txt. Maybe it is wrong in some way (e.g. "=" instead "==", that was my mistake).