ok I tried to get the server started again by /etc/init.d/ipsconfig_server start and it looks like it is working this way:
@server1:/# /etc/init.d/ispconfig_server start
Starting ISPConfig system...
Apache/1.3.41 mod_ssl/2.8.31 (Pass Phrase Dialog)
Some of your private key files are encrypted for security reasons.
In order to read them you have to provide us with the pass phrases.
Server www.cciinter.net:81 (RSA)
Enter pass phrase:
Ok: Pass Phrase Dialog successful.
/root/ispconfig/httpd/bin/apachectl startssl: httpd started
ISPConfig system is now up and running!
but I have never had to enter a pass phrase in the past.
what is the best way to fix this?