Thanks curious1960,
I still can’t log in by going directly to https://example.com/wp-login.php
I’ve also tried disabling the plugin folder (by renaming the folder plugin.hold in the server and adding a new blank plugin folder) and it’s not working.
I experience this problem using Firefox or IE.
Even if I type in the completely wrong username and password, nothing happens … the screen just goes back to the wp-login.php page – no “wrong username/password” message or nothing!