Hello there, @Syro.
Currently, we have an on-going issue where QuickBooks Online users are receiving an error when connecting the CIBC bank. Rest assured that our product engineers are diligently working on a fix.
As a workaround, you may want to consider manually uploading your bank transaction to QuickBooks Online via Web Connect. Please keep in mind that it will most likely cause duplicates once the issue gets resolved where you need to exclude those duplicates.
Here's an article you can read on for the detailed steps and information about Web Connect: How to Upload More Than 90 Days of Bank Transactions.
Also, I suggest contacting our QuickBooks Customer Care so they can add your account to the list of affected users. This way, you'll receive an email regarding the issue once updates become available.
Thank you for your patience as we work for a fix.