We have added portal counter for our high availability enterprise deployment. The test enterprise environment was recently upgraded to 10.9.1 and is able to collect result from the portal counter. However, the production environment is on version 10.8 and is unbale to collect result from the portal counter.
The site url is https://<machine_name.domain>:7443/arcgis
The token url is https://<machine_name.domain>:7443/arcgis/sharing/rest/generateToken
We also deleted the logs using both server and portal managers but still the counter is giving the same error.
UPDATE 1: We confirmed from our network department that our ArcGIS Monitor Server (Windows) is allowed to communicate with our high availability portal Servers (Linux) for ports 7443 and 22.