Battery charger starting problem

[Streetcar]

I have a Victron Skyalla 24v battery charger that wont start charging when switched on. If left switched on it eventually starts up and charges normally.

I am long term cruising so always use the 3kw Paguro generator for AC input. The part load Voltage is 220v and frequency is 50Hz.

Is it possible that generator output AC quality has deteriorated in some way that I am not measuring? If so, could this prevent the charger responding to the 'on' switch?