Your bank might not connect to all types of accounts (for example, personal accounts vs. business accounts).
The bank has system maintenance.
Some banks have multiple names on our list. You might want to check and select the correct one or try all possible bank URLs.
What you can do is reach your bank and check for any maintenance update or request to establish a connection with QuickBooks. If everything is good from your bank's side, ensure to select the correct bank name when connecting the account.
If the issue persists, I'd recommend importing the bank transactions manually as a workaround. This way, you can categorise and reconcile the account regularly.
Follow the steps below:
Sign in to your bank website and follow the instructions to download your transactions as a comma-separated value (CSV) file.
Go to the Banking tab on the left side.
Click the Link account drop-down and choose Upload from file.
Further, may I ask if you have received any error messages? And what is the name of your bank as well? This way, I can provide the most appropriate troubleshooting steps to help resolve the issue.
Do let me know in the comment section if you need further assistance with your online banking. I'm here to help you again. Keep safe, Jessica.