Please help identify and fix the UPS problem?! I have an EATON 9E 10KVA ups device When I switch the device to batteries, following behavior

I have an EATON9EKVA ups device. When the device is converted to batteries, the device exhibits the following behavior:1. The device without carrying: continues to work for seconds and then turns off.2. The device with the load: continues to work normally without any problems, but after returning the power supply from the main power source (electricity company), the device turns off. Note that the device is working normally (normal mode) to feed the current from the electricity company, knowing that the batteries are very good