Password Protected Pages

I have created Password Protected Pages a couple of times now and am having a problem.

The page appears on the menu and when I click the link to the page I get the expected result of:
This post is password protected. To view it please enter your password below:

The trouble is when I enter a password correct or not I get the same result – the page reloads and the password I just entered disappears and the page is ready for me to re-input the password. I would expect this if the password were wrong but it also happens when the password I enter is correct.

In searching this forum I have found that others have had this problem but the topics have been closed -resolved without any answers that will work for me.

I saw no way to re-open the topic so decided to post this as new problem.

I sure hope that I have explained this clearly and that someone can help.

Thanks

Steve