Additional info:
If I write: www.mydomain.xx/nextcloud/index.html in Chrome browser does it redirect to www.mydomain.xx/nextcloud/index.php and returns the HTTP ERROR 503
I have replaced my SD card and made a complete new Armbian / ubuntu installation: No improvements.
Running active servises: Samba sharing a mounted USB drive.
Can the reason be to LAMP installation taken from the armbian-config menu?
How can I verify if the PHP services is running correctly?