The Problem
You have installed the German language files (prompts) of the city of Pforzheim on your Asterisk system. The menu of your answering machine is German. But if you have only one message, the menu always will break off after the announcement of „Sie haben“.
The Cause
Asterisk wants to open the file 1F.gsm for the voice of 1 – „eine“. This file is missing.
The solution
The missing file exists under a different name, namely as eine.gsm. If you rename the file or even better create a symlink, it will work:
root@linux# cd /var/lib/asterisk/sounds/de/digits
root@linux# ln -s eine.gsm 1F.gsm