Perhaps this also works with the Apache module mod_vhost_alias? https://httpd.apache.org/docs/current/en/mod/mod_vhost_alias.html
It sounds like the ownership of the files is wrong.
Have you got a new router?
https://www.ispconfig.org/blog/ispconfig-3-0-5-4-patch-4-released/
It might also be helpful to enable PHP Errors https://www.google.com/search?q=php+display+errors+on
Propably it something to do with that issue? https://git.ispconfig.org/ispconfig/ispconfig3/-/issues/5419
Because the installer will install everything what is needed.
Probably yes. Did you try https://www.howtoforge.com/ispconfig-autoinstall-debian-ubuntu/ already?
You can also "chattr +i" that file.
You can also do this with a script that uses the ISPConfig Remote API:...
Probably a DNS issue. host -t mx hotmail.com hotmail.com mail is handled by 2 hotmail-com.olc.protection.outlook.com. host...
[ATTACH]
https://forum.howtoforge.de/threads/fail2ban-sasl-login-authentication-failed.13315/
What is if you change the "ü" to "u"?
You can use the ISPConfig remote API.
Separate names with a comma.