Square not connecting. error: There was a problem connecting. Go back and try again.

I wish you didn't have to go through this, @event. 

I'm here to give updates and share insights on the best step forward to resolve the error you encountered integrating the Square app with QuickBooks Online (QBO). 

Upon checking here on my end, there are several reported cases related to the Square app and QuickBooks Online (QBO) integration. I'd encourage reaching out to our Support Team again to submit an investigation ticket to our product engineers to resolve this error.

1. Sign in to your QuickBooks Online company.
2. Select Help (?).
3. Select either tab to get started:

• Assistant: Get quick, personalized answers. Select a suggested option, or type a question or topic you need help with. If you decide you need further help, you can still Talk to a human.
• Search: Search the QuickBooks Online knowledge base directly, or select Contact Us and choose a way to connect with us:
• Start a chat with a support expert.
• Get a callback from the next available expert.

As a future reference, let me add this article about connecting banks and credit card accounts in QBO: Connect bank and credit card accounts to QuickBooks Online. 

We'll be here in the Community if you have further questions or if there are details you'd like to add about the error you encountered integrating Square and QBO. We'll do our best to assist.

@event-eastfuelco 

Try opening your QBO account on any private/incognito browser.