Install error: `this app must be installed on a domain of its own`

[gordonhjs]

Describe the bug

Impossible to install Mobilizon, error message is Error: Sorry, this app must be installed on a domain of its own, but other apps are already installed on the domain 'chardon.ynh.fr'. You could use a subdomain dedicated to this app instead.

Context

• Hardware: pi4 at home
• YunoHost version: 11.1.11.2
• I have access to my server: Through SSH | through the webadmin
• Are you in a special context or did you perform some particular tweaking on your YunoHost instance?: no
• Using, or trying to install package version/branch: default

Steps to reproduce

   sudo yunohost app install mobilizon

Expected behavior

Mobilizon get installed.

Logs

Not much logs sadly:

$ sudo yunohost app install mobilizon
[sudo] password for admin: 
Choose the domain where this app should be installed [chardon.ynh.fr]: chardon.ynh.fr
Should this app be exposed to anonymous visitors? [yes | no]: yes
Choose the application language [fr | en]: fr
Warning: E-mail turned off for user admin
Choose an administrator user for this app [gordon | admin]: admin
Error: Sorry, this app must be installed on a domain of its own, but other apps are already installed on the domain 'chardon.ynh.fr'. You could use a subdomain dedicated to this app instead.

[yalh76]

Mobilizon need it's own domain, you should add a new one