Trouble with addon domains and mac

I always (have for at least 2 years) have trouble adding add-on domains. Whenever I create a new one, I get a spinning wheel in my browser, then it eventually times out. I try to go back and do it again, but it tells me that a dns entry already exists. Yet it is not listed in my list of addon domains. At that point, I can see it in the advanced dns entries, trying to delete it works, but doesn't solve the problem. (Adding again in addon domains tells me a dns entry already exists) At this point it just becomes a big mess. Any advice? Or help? If you can login, I currently have this problem with adhelo.us

I have tried this with both Chrome and Firefox browsers, and I encounter this problem almost every single time I add a new domain. I contact tech support, someone eventually fixes it, then I repeat 3 months later.