Tor browser (or other similar browser) users may get locked out occasionally because of the nature of the Tor system. Tor will change the IP address of the user approximately every 10 minutes to keep them anonymous. In doing so, it will sometimes use an IP of another person that may have used the IP to attack systems in the past. Unfortunately when someone want to attack systems anonymously; they can use Tor to change their IP also. On protected systems this may lock out an IP that they have used and in doing so another user of the same IP will also be locked out. This is unfortunately; but a necessary evil that must be dealt with to protect our users.