The most important feature is, that the default works for every app and user without tedious setup, like now “english” is the default, it should be possible to change it it “german is the default”. IMHO in most installations all users will use the same single language in all applications.
“Force language” could be an option, but there is no real need to prevent someone to use a different language. If implemented it should be an only an option.
It is not just for two applications but all application to now and to come, where it is possible to change the default language.
I restarted Apache and also reboot the server but still the same issue.
Reading along this post I haven’t found a clear answer but did not want to start a new thread with same name.
In case you haven’t noticed, this is the NethServer Forum, not Ubuntu. NethServer is based on Centos7, so the basics are very different.
Try on the Ubuntu server forum - or install NethServer and get help here.
On NethServer, it works more or less “out of the box” - and for several years.
But as we don’t base of Ubuntu, we can’t really help you here.