Websites have stopped responding, how to troubleshoot?

They should be in the file /etc/group.

 

Are there any older copies, eg. /etc/group~ or /etc/group.old or such? If not, check your backups, including those made when you last updated ISPConfig. Using someone else's isn't good, as most entries will be different, except for a few core groups that would be setup identically on all debian systems; you can refer to your home debian system as an example, but maybe start with:

Code:

root:x:0:
daemon:x:1:
bin:x:2:
sys:x:3:
adm:x:4:
tty:x:5:
disk:x:6:
lp:x:7:
mail:x:8:
news:x:9:
uucp:x:10:
man:x:12:
proxy:x:13:
kmem:x:15:
dialout:x:20:
fax:x:21:
voice:x:22:
cdrom:x:24:
floppy:x:25:
tape:x:26:
sudo:x:27:
audio:x:29:
dip:x:30:
www-data:x:33:
backup:x:34:
operator:x:37:
list:x:38:
irc:x:39:
src:x:40:
gnats:x:41:
shadow:x:42:
utmp:x:43:
video:x:44:
sasl:x:45:
plugdev:x:46:
staff:x:50:
games:x:60:
users:x:100:
nogroup:x:65534:

That's from a Debian 10 system, so probably find a better one if you're using something else. And that is *very* incomplete (many of your services will still fail to start), but I think most accounts under 100 are pretty standard name<->id's within a distribution version.

 

Above group id 100 all the I'd numbers are a located sequentially from various ranges, they are not set, so you can't just copy then from another system, or almost all of them will be wrong. The mess you will create by using the wrong IDs might well be more difficult to clean up than the process of determining the correct IDs (which you have to do anyways). You can't find even a single old version in a backup somewhere? That would be much safer to start with

 

You could rebuild most of the group file with some effort, but this is not the first trashed /etc/ file you have had in this thread, so if you have no backup, then yes, probably abandon this server and move to a new one.

 

You would have to find it what group names you need, and what I'd each should have. You could try installing the same software in a test system to see what groups you have, and hope to identify the correct IDs. (eg find files set to the group on your test system, then see what gid they have in your broken system). The ispconfig groups could be determined from website files.