This week's book giveaway is in the Reactive Progamming forum. We're giving away four copies of Reactive Streams in Java: Concurrency with RxJava, Reactor, and Akka Streams and have Adam Davis on-line! See this thread for details.
I don't know what to say, I tried the registration process myself just half an hour ago and it worked ok.
I tried putting in nothing or nonsense and it popped an alert telling me which field was in error, which is different to your report. Also, I repeatedly entered nonsense many times and have not been banned.