Help solve the problem with the generator

Good hour to all. Help to understand the problem. I'm not special, but I understand something. There is a country house. There is a shield. There are three Resant 8000 stabilizers. I decided to make a reserve, set the ABB circuit-breaker and energized one phase in case of a power outage. In general, a few days ago I rented a five kW generator. I connected and started - the usual LEDs blinked. In general, the consequences - the stabilizer does not work, the screen shows the input and output voltage, but there is no output 220. I had to switch to bypass. And how to make zero on the generator? Thank you all in advance.