Yeah, it's common to have bad url or email address validation. Many sites do not accept short email addresses at all. As example a @bc.de (space is there intentionally). When it becomes a @ bc then it's interesting to see how many sites will fail with that.

I believe that TLDs with A records should resolve correctly if you add a period to the end, as in "http://ac.. As I recall, this came up when the "http://to. link shortener [no longer available] was discussed a while ago.

What browser are you using? This worked in my browser.