You mentioned earlier that your app host is localhost:3000, so that’s basically the dev server being referred to. Each artboard is in iframe into that application, so that’s what connections is referring to.
When you turned off design mode, do you mean that the one artboard is blank?
When you pull up your Chrome developer tools, do you see any errors or other log messages from your app?
I think the thing that is usually guaranteed to help in this kind of situation is to debug by comparing against something that is known to work, so for instance starting from a brand new create-plasmic app, verify that that works on your machine, and then incrementally make either your new create-plasmic app or your existing app more similar to the other one, until the problem is either reproduced or no longer reproduced.
“When you turned off design mode, do you mean that the one artboard is blank?” yes
“When you pull up your Chrome developer tools, do you see any errors or other log messages from your app?” No.
And I can send you a screen recording if you want.
That indicates it’s a problem coming from your specific code base. Can you try with a brand new create-plasmic-app to confirm that the problem doesn’t exist there? And then you can start comparing and contrasting the differences between the two code bases, trying to make one more similar to the other until the problem is either reproduced or no longer reproduced