So be sure to "Exit" the browser - some will work if you click the three dots to get a dropdown menu and you'll see the option for "Exit."
Once you're able to get back to the log in screen, try to log in again. Usked doesn't have a lock out feature but instead uses the browser to lock the user out of the browser session after three failed log in attempts. Exiting the browser and opening it back up should resolve the session lock out.
If this doesn't work, try either clearing your internet history/cookies, re-booting your computer, or opening and trying to log in using a completely different browser, or opening up a new window in your browser using incognito mode.