You can bring up the console by choosing More Tools -> Developer Tools from the Chrome 3-dot menu:
Then, when the Developer Tools window appears, click the “Console” tab:
Next, navigate to the page in Confluence containing your Balsamiq project, edit the page and try to edit the project. Don’t worry about any messages which appear in the Console window. Just get to the point where you’re in your project and the screen is blank.
You can then right-click in the Console window and use “Save as” to save the contents of that window in a text file. Once that’s done can you email it as an attachment to firstname.lastname@example.org and we’ll examine it.
I know this is fiddly and a little inconvenient, Mario. if it would be easier for you to set up a screen share and have me remote-in and run through this for you, I’d be happy to schedule a call. Let me know.