Hi there, SNLLC.
Thank you for providing detailed information about what you did on your end. I want to help share some information about this error message.
I've checked here and found some reports coming from other users about this error specific to the Canada region only. May I know what QuickBooks Online version you're currently using now?
Since you've already tried performing all the necessary troubleshooting to fix the issue, I encourage you to give us a call this time. Our Phone Support Specialist will need to check your account and perform any actions they need to fix the issue on your end.
I'm adding the steps below on how you can reach out to one of them:
Thanks for coming to the Community, I'll keep an eye out for your response.