Problems with creating an account
It is known to us that there are problems with receiving the confirmation e-mails to the @gmx.de *) and @web.de e-mail addresses. 
It seems to be a problem with the spam filter of web.de and gmx.de.
Our webhosting company has contacted gmx.de and web.de about this.
You can for the time being, better use a Gmail address (also free)

*) For Austria also with @gmx.at address