Thanks for turning to the QuickBooks Community for support! It's important that your able to connect your account and download all your bank transactions without running into any issues. I encourage you to take a look at this helpful guide to help you successfully connect your BMO account.
If you require further assistance, I recommend reaching out to the support team outside of the Community. They'll be able to verify your account details in in a secure setting, as well as view your screen to better assist you. You can reach them by following one of these methods:
Schedule a Callback or start a Chat: click (?)Help in the upper right > type and enter "Contact support" into the QB Assistant > click Contact Us > explain your situation > click Let's Talk > choose Get a callback or Start a Chat. Social Media: Facebook and Twitter
If you have any other questions, feel free to reach out here.