Aria Operations for Logs 8.18.x
Operations for Logs is an endpoint, it does not 'retrieve' logs from sources.
Log Sources, like ESXi or vSphere are configured to send logs to the Operations for Logs cluster.
In order for logs to be received on the Operations for Logs cluster specific ports need to opened between the source and the cluster.
Information on what ports are required can be found on the VMware ports and protocols page, linked below: