Let’s try some workarounds to verify if this is a browser-related issue, @Craigsat.
 
As of now, there is no similar reported issue. I recommend using a private browser to see if you can find your bank account in QuickBooks Online (QBO).

Here's how:

• Press Ctrl + Shift + N keys on your keyboard (Google Chrome)
• Press Ctrl + Shift + P keys on your keyboard (Firefox or Internet Explorer)
• Press Control + Option + P keys on your keyboard (Safari)
 
If you can locate your bank account to QBO after doing the steps above, go back to your regular browser and clear your cache.
 
In case if you’re still not able to locate your bank account, try to edit your sign- in information. If still not able to do so, it's highly recommended to call your financial institution to verify and have documentation to be submitted to QBO through contacting support team.
 
Also, I provided articles for you regarding bank error 106.

For future reference, you can check this article on what to do if bank if there's a bank error.
 
Loop me in if you have other concerns regarding QBO. I'm always here to help. Take care.