HP R5500 XR UPS won't show up anymore

[Wibo]

During last night I received an e-mail from our power manager that the connection with the remote agent of the ups was lost.

When I went to check out the UPS this morning I noticed that the overload and the on battery led indicators are both continuously red. There is no beep alarm and the ups is at 25%. There is no power outage.

I can still ping the UPS's ip-address, but I cannot connect with it.

Pressing the control buttons doesn't do anything, the UPs only beeps when I press a button.

I've tried connecting to the UPS through telnet, but without any luck.

What is going on and what can I do to fix it?

The UPS's warranty has expired, but the batteries are brand new (only a couple months old).

PS: I'm unsure if this is the correct forum for this question.