Remove a client from Icinga2

Hello,

I am new to the topic of Icinga.
I would like to delete a client from Icinga that no longer exists.
I thought it is enough if I delete the host file in /etc/icinga2/objects.d/hosts.
But unfortunately the host remains with errors in icinga.
How can I remove this permanently.

Thanks

Jochen

Icinga2 r2.8.1-1
RHLES 7.6
Enabled features: api checker debuglog ido-mysql mainlog notification perfdata

Hi & welcome to the icinga community,

After changing any conf file you need to reload icinga:

systemctl reload icinga2