If you get blacklisted/locked out despite of having your IP whitelisted with Shield, please ensure the IP address source under General Settings=> Plugin Defaults is correct. 

You can use the Welcome Wizard to set that up.

If this doesn't help, please use Audit Trail Viewer to review your site activities:


It will tell you exactly what's going on, what's being blocked....so you could get the problem resolved.

Note: In case you get locked out of your site, follow the guide outlined in the article here.