We’ve recently seen quite a few failed brute force attacks on clients’ websites. What that means is that a computer somewhere (seems like mostly Russia) will try to login repeatedly using different passwords until it gets in or is denied by security software.
You should check your site to see if you have a security plugin installed to protect against this. In the site admin section look under Plugins > Installed Plugins. If you see the plugin Bullet Proof Security listed then you should be fine.
If you don’t have it installed contact us and we can do it for you, or if you’d rather give it a try yourself you can get it here https://wordpress.org/plugins/bulletproof-security/ (it’s free).