Thank you for posting here in QuickBooks Community. Can you please share with us the specific error message you received? I'd appreciate any further details so I can present accurate information.
In the meantime, I suggest logging your QuickBooks account using a private browser. This is to rule out the possibility of a webpage issue, and private browsing doesn't store local files or cache. This might be also the reason that you getting an error every time the program idles for minutes.
Use these keyboard shortcuts based on the browser you're using.