The error message below has to be one of the most funnier in a long time ...
So did I succeed or not? It says "Success" but at the same time it's an error. Confusing is surely the least one can say ;)
So what was I doing then? Well, I was about to move / re-install a KMS server on Windows Server 2012 R2 and when I got to the last page and clicked "commit", I got the error message.
The cause of the error and also visible in the picture below is that the wizard does not enter the right "KMS TCP listening port" automatically. The port should be 1688 and if you enter this the wizard goes through.