Hi @Basil3. I can share a little help with connecting your Scotiabank account to QuickBooks Self-Employed (QBSE).
I appreciate that you have already run a couple of steps to isolate and resolve this issue further. Aside from the tests you have tried, you can also sign in to your bank account outside QuickBooks. Then, check to see if there are maintenance updates.
On the other hand, some banks download the file in a different format like PDF or Docx rather than the CSV composition. Make sure it's in the correct format (save it as a CSV file format) before you can match the column headers and order in QBSE. You can read this information for the process: Manually import transactions into QuickBooks Self-Employed.
I also suggest contacting our QBSE Support team. They have the tools to see and fix the connection between your Scotiabank and QuickBooks.
All I want is to get this resolve for you. If you have other questions in mind about connecting your bank to QBSE, feel free to post them here. I'm always available to help. Take care!