If you’ve lost power, it’s beeping to let you know that the battery is in use, and that you should save your work and shut down your computer. A constant beep (every second or two, and never stopping) generally means the UPS is very low on battery power, and you should shut down immediately.
If there’s been no power loss and it’s still beeping periodically, your UPS is letting you know that it’s failed a self-test. If you’ve plugged any power-hungry devices into it recently, unplug those first and see if the beeping stops. Otherwise, the battery may be in need of replacement – the UPS is letting you know that, if the power fails, the device won’t have enough power to keep your computer operational.
If you want to keep your data safe in the event of a power outage, don’t ignore it or unplug it! Give your IT team a call or send them an email and let them know they need to come take a look at your UPS. Like anything with a battery, they do need replacement periodically.