Can't create Open DNS account pw not accepted

Please could someone resolve this.  I've got 3 boys and have been without parental controls on the new Nighthawk router for weeks now. The router works fine and has resolved all the lagging game issues but I can't set up the parental controls and I really need to.

I note the recommended solution to pw not being accepted in the create new open dns account box was to input passwords of 12, 13, 15 or 16 digits with special chars, lower and upper case etc.  This isn't working for me and I've exhausted all combinations I think.

How do I create an account so I can get these parental controls please? If i have no luck with this I'll have to return the router.

By the way the validation on this site is not great either! Can't you simplify it for dummies like me?