As we know, there is a built-in option in WP to protect a certain page with a password. Under the general settings for the page, I choose to show it only with password and set the password accordingly. When visiting the page, indeed there is a text box for typing in the password and submit button.
The problem is that when I type in the password I set (the right one, I swear) and click the submit button, the page just reloads and shows the password text box again, without showing the regular content of the page. Without any error message, the password is absolutely right, and no indication why it is acting like that.
Now, I have looked around for it, and everything I've found is talking about a problem with the URLs of the site, as the reason for this situation. Well, I have no problem with the URLs of the site, as both are the same, as they've always been from when I created this site.
So, what is the cause of that? Is it a bug in WP that still exists in 4.9.1? I don't think the issue is related to cookies or something like that in the browser, because cookies are not blocked (and it happens on every computer I've checked this on).
UPDATE:
I forgot to mention that this situation happens regardless to cookies. Meaning, it will happen also on a computer that has never been to this page, or in Incognito mode of Chrome for example, and even after deleting all the cookies of the site and refreshing the page.