Email I want to register with is not valid.
I ended up using a yahoo email to sign up because it wouldn't let me use my hotmail email. What do you have against hotmail? It's been my main email account for more than a decade and this is the only site that has ever denied me using it. It seems so arbitrary and actually makes me kinda mad, just because it seems to arbitrary to deny use of hotmail accounts.
Edit: I found I was able to successfully change my email to hotmail now that I am registered so I guess I don't need any support, but I guess that means this is a bug with the site? I hope it is at least.