HC Custom WP-Admin URL and WPMU staff support access

I think I added HC Custom WP-Admin URL plugin to boost security in the past and that cause the support access to be blocked. Is there a way around that? Or do you suggest some other security measure?

I have been getting a lot of WP lock outs that give me a there error of - My Sit is undergoing a Brute Force Attack and that I will not be able to log in for 20 minutes..

thanks,
Matt