OCS interface SNMP

Hello,

I want to inventory my network equipment via snmp.

I followed the tutorial "05.Network Discovery with OCS Inventory NG » Using SNMP scans features

But i have no inventory equipment (swtich firewall ...)  and I do not know or look for log in order to know the origin of the malfunction.

Merci.

Serveur : ubuntu 18.04.1 LTS Apache/2.4.29 (Ubuntu)

OCS report 1:10.3.10+maria~bionic-log 2.5