Login Pop up doesnt appear

Well, when im trying to leave a comment, here is button “Log in to post”. When I click this button pop up window appears and immediately closes, then appears again and closes again. It happens for around 10-15 times. So as far as you understand I can’t post a comment.
My browser is google chrome with no plugins. Inkognito mode doesn’t fix this issue as well as the Safari browser. In safari, I have to click the accept button on a notification where its told facebook will get my data.

So, pls let me know what can i do in this case ?

Thanks