Circuit Advice - MCP23017

I have a MCP23017 (PR20-4) 16-Channel 8W 12V FET Solenoid Driver Valve Controller with I2C Interface. I have no problem using the device, however, recently I have changed solar charge controllers. I am now using a Sunsaver 12V-SS-6L. Unfortunately, this board and the solar charge controller do not like each other. If I connect this board directly to the load on the charge controller, then I receive an error that is indicative of load overcurrent, load short circuit, or external wiring error. I have 2 of these boards and I am receiving this error with both boards. Even if I remove all of my solenoids from the boards. Therefore, I am trying to come figure out how to solve this issue. One of my ideas is to add a resistor in series. However, there is unfortunately very little information about how much current this board draws or what the in-rush current might be. Any advice on how to size a resistor for this board. Any additional ideas on how to reduce solve this error? Any advice is appreciated, I have a very limited background in electronics and I am hoping to learn more.