Thanks for reaching out to the Intuit Community. I'm happy to assist you in connecting your bank account.
To make sure I can provide a timely solution, can you share with me the exact error code or message when connecting your Bank of America? At the moment, we currently have an open investigation (INV-44240 & 44247). Our product engineers have released a workaround for the time being. Any updates about the status of this issue will be announced via email.
If you received a different error code, you can also check this topic: What to do if bank transactions won’t download, refer to Step 3: Fix specific banking errors. It includes a list of common banking errors and their fixes.