You need to switch the unit on. To do so, press and hold the two buttons pointed to by the 'On' text
The unit has the Emergency Power Off function activated. The EPO can be activated using the EPO port on the rear of the unit, or by pressing all three buttons on the front panel simultaneously (note this can happen by accident when you lift the unit out of the box). The unit cannot be reset until the EPO activation has been reset. To do this, either re-engage the switch connected to the EPO port (or refit the connector), or press all three buttons on the front panel again.
The unit has the bypass function enabled but is switched off. The alarm is to tell you that there is no UPS support. Turn the unit on by pressing the two buttons pointed to by the 'On' text. See photo above.
The unit is connected to a supply with a floating earth or inverted live and neutral. This is common on Schuko plug connections where the polarity can be inverted simply by rotating the plug.
Note that the VFI-B series battery connections are via the front panel and all connection leads are built into the UPS and the battery cabinet. No further leads are required.