Installing packages forever without any success when I try to install from Settings

I installed Anaconda, and now my interpreter in PyCharm is conda interpreter. I want to install packages from Settings - Project Interpreter - + button, but I can not install packages from here. (my conda version is 4.7.12 and I installed Anaconda and Pycharm just today with latest versions.)

When I search a package and click install button, the 'installing' sign never stops, and the green sign of success does not appear.

When I check the background task, it also shows a blue bar with forever loading loading loading.....to install a package.

How can I solve this?