Not able to install packages in Pycharm

I had the same issue. It happened suddenly, day ago I was able to perform pip or install packages but on the next day error appeared. However this helped (I used version PyCharm Community Edition 2018):

Go to Settings -> Project Interpreter -> click green "+" icon (on right) -> Manage Repositories (on bottom) -> delete https://pypi.python.org/simple -> add https://pypi.python.org/pypi then click Ok. Repo will be back again as /simple, but don't worry, error should disappear and you should be able to install packages again.

I have got a solution, i reffered to https://youtrack.jetbrains.com/issue/PY-20081#u=1468410176856.

Here they have tried to add https://pypi.python.org/pypi as a repository.

To add it as a repository,

1.) Go to Settings
2.) Project interpreter
3.) Click the + sign on top right edge
4.) Go to manage repositories, 
5.) Press the + Sign, then add https://pypi.python.org/pypi
6.) Press Ok

Now all the packages should load.

Thanks Hami Torun & Simon, I was able to solve it by luck.