Antivirus (Clamav) Can't save mode socket in Admin panel

My server info:
Operating system: CentOS 7
Apache 2.4.6
PHP version : 7.1.8
ClamAV : v0.99.2 clamd daemon installed on host listening on local Unix socket /var/run/clamd.scan/clamd.sock
NextCloud version : 12.0.2.

I just try to configure ‘file_antivirus’ apps.
Getting the apps from git hub (branch master) and enabled through apps panel works fine.
I changed owner/group of files_antivirus apps to apache:apache to be readable by the web server.
Unfortunatly, i can’t change the config of the app from ‘antivirus Configuration’ menus.
No matter which mode i choose, Daemon, Daemon (Socket),… ClamAV remains in ‘Executable’ Mode.
This make use of clamscan (which is very very slow analyzing files) indeed the unix socket in daemon mode.
Seems like it is not save even when i click save. This append only for this app
May be a problem on right access on files ?.. but where ?
Has anyone ever encountered this kind of problem?