My Site keep causing an IP Block

I have an intermittent problem that is really annoying. My WP site has caused various IP addresses to become blocked. Last time it happened simply by loging in to Admin, though at first I thought it was caused when I updated a post and tried to view the post too fast. Symptoms are, cant load any domain that is on the (shared) server, but can load the site from any other location. This isn’t an issue with my ISP as it has happened in 3 different locations. When I contact my host they fix it up but cant tell me what triggered it.

I’m guessing it has something to do with my WP installation or my theme or the server itself. But its so intermittent I cant trigger it to troubleshoot. Any ideas or help would be much appreciated.