I don't own a Zappi, but my understanding is that AC chargers to not receive the SoC from the car, so the Zappi doesn't actually know that the battery's full, but rather it's guessing because the car isn't calling for power.
I would try disabling Eco+ mode first. I see that this charges at 1.4kW when your own generation is above 14W. My car stopped charging on a granny cable when that fell below 1.7kW (for unknown reasons), so perhaps the car just refuses to charge slowly sometimes.
If you left the car for a long time, and Zappi was going start charging in the morning using solar power, it might have gone to sleep to preserve the 12V battery and the Zappi can't wake it up. Try setting a schedule for the car for the same time you want the Zappi to charge it and see if that resolves it. My personal method to solve this problem - which I experienced once - was to tell the car to charge from the API when my charger wanted to charge, but I appreciate that's on the extreme side.