C is null go js, I have no idea why this error

I have no idea why this error, I get when I load the model of my diagram and it does not show me the inspector but it lets me create new nodes and relate them in summary I do not know what this error is

That error is probably due to the previous error, which is probably the root cause. That is the JSON.parse error. Basically, the problem is that your JSON-formatted text has a syntax error in it.