OMS-Agent Onboarding Error

We are trying to onboard ApacheHTTP server to Sentinel using OMS-Agent, after installation we run to the troubleshooter and have the following error:

ALL ERRORS/WARNINGS ENCOUNTERED:
ERROR FOUND: file /etc/opt/microsoft/omsagent/conf/omsadmin.conf doesn't exist.

We tried with two different Linux versions : Centos 7.2 and RHEL 7.9
Same problem is encountered.

Any solution for that?