Some people reported that they never received the sign-up email, and so they couldn’t finish the sign-up process. We’re very sorry for this inconvenience.
The problem was that the sender address for outgoing emails was using a domain name without an MX record. It seems for many email providers that’s not an issue, but for plenty it is, with the result that about 20% of our emails were being dropped.
I’m sorry this rookie mistake has caused some frustration. @martinklepsch and I are working to approve the remaining accounts and contact the people affected. If you don’t hear from us in the next day or and you’re still unable to use your account, then please get in touch (firstname.lastname@example.org).