If you are encountering this error, there was an communication( I2C) error between different units of the printer. This could either be a fault within the mainboard, or miscommunciation between the Ultimaker 2+ Connect and the Air Manager.
To resolve this error, please check the connections between your printer and the Air Manager.
If the problem persists, there may be an issue with your mainboard. Please contact support by raising a ticket above.