I am trying to debug a canvas app and as per the documentation i tried the following code snippet in developer console in execute anonymous window.
Debugging in a Canvas App
You must use Chrome, Firefox, or Safari to follow these steps.
When using the Force.com Canvas SDK, you can enable debug mode to make troubleshooting easier.
With your canvas app open in your browser, open the console. Type Sfdc.canvas.console.enable(); and press return. Refresh your browser.
Use data from this screen to debug canvas-related problems.
But i got the following error,
I have been executing all the canvas app through "Canvas App Previewer".
Any suggestions please.