Getting the dialog box open seems a little convoluted, perhaps if you have already visited the site and taken a cookie.
It should load as soon as you hit http://www.atcormedical.com/, however it doesn't for me possibly because I've already signed up.
If I use an incognito / private browsing window, the box shows up, and I can register.
Also check your junk mail - that's where I found the confirmation.
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