If you ever got locked out (blacklisted) of your own site as a result of Shield, for whatever reason, you can forcefully turn off all restrictions made by it by using a 'forceoff' file. This will temporarily turn off all Shield features allowing you to get back in and remove your IP from blacklist.
The another way to regain access to your site and remove your IP address from blacklist is using the 'unblock' file flag. This is how you can do that...
You got blocked by Shield:
To unblock your IP, you'll need to log into your FTP space for that site first - we recommend FileZilla.
Then, browse to the plugin folder: ..../wp-content/plugins/wp-simple-firewall/ and create a file called 'unblock' in the 'flags' folder. It can be 'unblock.txt':
Once you've done that, click to edit file and put inside it the IP address you want to unblock and then save:
The Shield will automatically unblock the IP. All you need to do now is to reload the site.
Hint: You can also see this activity in your Audit Trail: