The Light is a Warning
The trouble light and trouble tone are on the fire alarm system as a warning: Something's Not Working
. As long as something's not working on the fire alarm system, the trouble light is going to stay on.
In order to tell the fire alarm panel that you know there's something wrong with the system, the annoying trouble tone can be silenced . . . but the trouble tone will resound in 24 hours to remind you that there's something wrong with the fire alarm system.
In order to turn off the trouble light and trouble tone, the system has to be fixed.
Fire Alarm System is Not Working
Whenever there's a trouble light showing on a fire alarm system, you can assume that the fire alarm system doesn't work at all.
"DLC @ Address 2, Trouble Type. Module"
showing on the display probably indicates that the Digital Loop Controller module on the panel is not working. This module controls a lot of the devices in the building. If there's a fire, there is a good chance that the fire will not be detected until the fire is very big.
Remember, there may not be people in the building due to the pandemic, but as well as for "Life Safety", the fire alarm system is there for "Property Protection". If the fire alarm system isn't working, the building is not being protected.
Talk to Siemens Technical Support to find out what you can do about the trouble. It may be something simple, but then again it may be something expensive, like the Digital Loop Controller.
Check the Circuit Breakers
Just thought of another possibility. I've seen this problem where part of a building is shut down because it's not being occupied at the moment.
Circuit breakers were turned off, which turns off parts of the fire alarm system. Check the circuit breakers. If the circuit breakers were turned off to save money, turning off the circuit breakers could also have shut down part of the fire alarm system.