Seeed-IoT-Button-for-AWS: App cannot login to AWS

Received the new IoT-Button-for-AWS (and had to order that special battery first additionally, which was an annoying user experience). Cannot get it into my Wifi as it requires the AWS Login on the iPhone App. After the eMail and Login Captcha I can see only the spinning wheel. Nothings happens after that. How can I get it working?

What can I do?