The "Test" button is unsuccessful in Environment Monitoring. How can I verify that the sensor is functioning?

First, you would need to verify which COM port the sensor is attached to. In this example, we will use COM3, but you would want to specify the COM port that your sensor is attached to.

To test whether the sensor is able to be queried via COM3, you can download putty.exe (https://www.chiark.greenend.org.uk/~sgtatham/putty/download.html) and then open an administrator-level command prompt to launch putty.exe, and then on the first page of the settings choose "serial" as the connection type and specify COM3 as the port at the top, and then click the "Open" button at the bottom of the putty settings to connect to the sensor. If the sensor is able to be queried, the putty terminal will repeatedly display the current sensor values and keep writing a new line of the values every second. The putty settings and example of sensor output are shown in the attached screenshot.

Some problems are a result of the sensor needing its driver to be installed, the sensor driver installation instructions can be found here:
https://www.eventsentry.com/kb/213