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.