Thank you for reaching out to the Community space for assistance with your Monzo bank transactions in QuickBooks Online (QBO), Ian. As a fellow QuickBooks user, I understand how frustrating it can be when bank transactions don’t sync properly.
I'll walk you through some troubleshooting steps to get your bank transactions to sync smoothly with QuickBooks.
Before that, I recommend logging in to your bank website to check for ongoing maintenance or a temporary outage. You may also want to contact them to see if they've reported any known sync issues on their side.
If everything works fine, let's manually update to force the transactions to be downloaded from your bank.
Here's how:
- Go to My Apps.
- Click on Accounting and select Bank transactions.
- From there, locate the bank account.
- Next, select the Update button.

If this doesn't resolve the problem, I suggest uploading your downloaded bank transactions to QBO using the Upload from file feature.
Here's how:
- Go to My Apps, then click Accounting.
- Select Bank transactions and click the dropdown arrow beside the Link account button.
- Click Upload from file.

- From there, you can choose the file you want to upload.
- Click Continue and select the account for the bank file you want to upload.

- Follow the on-screen instructions, then click Done.
You may refer to this helpful resource for more detailed information: Manually upload transactions into QuickBooks.
Please don't hesitate to use the Reply button below if you have any further questions.