Hello there, @TVindett. Thanks for the details. I'm here to lend a hand.
To start with, upon connecting bank account, it is a need that you must have an online banking set up with your financial institution before you can connect your bank account with QuickBooks. You can check with your financial institution for guidance about setting up online access to your account. Also make sure that you've able to meet the following requirements for Online Banking setup and download:
- Performed a successful download of transactions from your bank to this QuickBooks company file.
- Able to log in to your account outside of QuickBooks through the website
To help us resolve the issue, here are the steps that you can follow in order:
Solution 1: Create a new test company file.
Solution 2: Create a new account, then merge the accounts.
Solution 3: Deactivate ALL accounts with online services.
Solution 4: Download a new FIDIR.txt file
Solution 5: Contact your bank
For more detailed steps with guidance, here's an article that you can check on: Troubleshoot Online Banking (MAC).
For future reference, I'm also attaching a helpful guide for you to use about QuickBooks Desktop for Mac 2020.
If you have any follow up questions, let me know by commenting below. Have a great day!