Hello FrankAusNRW,
thanks a lot for your answer. That’s exactly what i had done right after the apache-server wasn’t reachable anymore.
Could it be that my config file corrupted something? That’s the content of the File:
<VirtualHost *:80>
ServerAdmin webmaster@localhost
ServerName meine-solaranlage.de ; the original "domain is the myfritz address from the Fritzbox"
ProxyPreserveHost On
ProxyPass / http://192.168.178.1/
ProxyPassReverse / http://192.168.178.1/
ErrorLog ${APACHE_LOG_DIR}/solaranlage_error.log
CustomLog ${APACHE_LOG_DIR}/solaranlage_access.log combined
</VirtualHost>