multi server - app installer - dbserver 127.0.1.1 should be 192.168.....

Hello,
in a multiserver setup with dedicated portal-, web-, db-, dns-server I can't install apps into webspace on web-server.
The installation breaks because of wrong ip address for db-server 127.0.1.1 as shown in ispconfig/cron.log on web-server.
127.0.1.1 is set in aps_instances_settings on portal-server in dbispconfig.
Correct values are 192.168.10.81 or isp-db01.xxxx.local

Any help appreciated

Regards
Gerd