500 - IoT Edge Runtime Error occurs when trying to implement modbus module on Azure IoT Edge Device

Basically what the title says. I am using the github repository for this modbus module (https://github.com/Azure/iot-edge-modbus#configuration) and am following their instructions for setting it up. The module itself was working when I first implemented it, but when I came back the next day, I was getting this 500 error. When checking the iotedge list - the module was not listed, and the logs do not show it even attempting to start. Tried deleting the device and then redoing it all - same issue occured and I am now entirely unsure as to what to do. 

Just to add onto this, I was also following this little tutorial to make sure I didn’t mess up somewhere: https://docs.microsoft.com/en-us/azure/iot-edge/deploy-modbus-gateway