Must hybrid inverters are designed to communicate to you through error codes.
Error 56 would mean
1. The Battery connection is faulty or open. Battery not connected
2. Check all Cables, Restart your Must Hubrid inverter, check all your fuses including MCB and Battery Fuse
3. Empty Battery bellow minimum required limits may also affects and may display Error 56 in your hybrid inverter. Consider boosting to revive your battery and re connect...