As of Sept 14, 2021, my "Connect to Square" app has stopped working. No imports are coming in to quickbooks from square sales.

Have you tried open your QBO account on private/incognito browser?

Yes I have.  The transactions are no longer flowing from Square to QBO using the Intuit created app integration.

Yes I tried doing this but the transactions are still not flowing through from Square to QBO. 

Consider using the trial version of other connectors to isolate the issue.

I will consider that - bummer that the free one developed by Intuit doesnt seem to have any support.  I called their support number and they said they are not trained to assist with it.

I also tried removing the app and re-adding. This seemed to work but it duplicated some of my entries which has caused a different problem.  Argh.

I am experiencing the same issue, I have to disconnect and reconnect the app each day, do a custom import of the prior day and it syncs. Not sure why the automatic sync stopped working, but it is quite disappointing that Intuit will not acknowledge and fix the issue.

Thank you for joining the thread and sharing your issue with us, @PYRC.

First of all, I appreciate the troubleshooting steps you've performed to sync your square transactions into your QuickBooks Online (QBO) account. I'd like to redirect you to the right support group to get this fixed.

Since the syncing of transactions stops working, it's possible that the Square software had issues connecting to QBO. In this case, I suggest reaching out to the Square customer support team to get this check. This way, their support team can look further into this issue and provide some steps to get this resolved.

Just in case you want to learn more about the integration between Square and QBO, you can read this article for more details: Sync Square with QuickBooks Online.

Please feel free to keep in touch with me here on your progress with this syncing matter, I want to make sure you're taken care of.