If you see the message " 'up.time Data Collector' is unavailable," in the Monitoring Station GUI, this is likely the result of a mismatch between the hostname Uptime Infrastructure Monitor is trying to use to connect the Core/Data-collector and where the service is actually running.

The reason may be you have installed Uptime Infrastructure Monitor for the first time, or changed the hostname of your Monitoring Station. 

This can be resolved by updating the uptime.conf with the correct hostname for your server: