I had this same problem. The error message was: Oops, sorry an error occurred! Either you left the languages field empty or <EMAIL> might be already registered. Please contact us if you require further assistance.
Can you still not sign up? Please email us with the address you use at info@askadev.com.
I could sign up to learn, but not to learn and teach apparently.
Thanks for signing up and we're adding that option shortly. Email me at info@askadev.com.