[APC Smart UPS SRT 3000] p.13 error

[Therradan]

Hello,

One of my three remote Smart UPS SRT 3000 is down with the P.13 error.

What could be the cause of the malfunction?
I didn't find this error code in the operating manual.
However, on other models, it indicates an “inverter fault”. What does this mean?
Absolutely nothing has happened on the electrical network and no manipulation has been carried out. The inverter's load has always been low because it drives a mini computer and the internet box

Consequently, I don't have the logs, but I asked a colleague on site to plug the internet router into a normal electrical socket to access the inverter's logs.

Is there a procedure to check that this is not a false positive error?

Best Regard,

Jo