Ink bird and Eheim

I just installed a ITC-308 Inkbird. My Eheim heater worked for a moment and then no light indicators came on. I was scared the controller was causing problems. I took it offline plugged into wall. It took a bit but then the indicator lights green & red lit up. Do I have a defective inkbird. I notice the plug ins for heater and cooling are very narrow making it difficult to to shove in the plugs. Is this normal?

Could a inkbird trash a heater?