I've put together some troubleshooting steps to assist you in seamlessly syncing your Monzo transactions and balances with QuickBooks, @Eversafe.
Before anything else, may I ask if you've encountered a specific error in QuickBooks? Any additional details provided would be much appreciated as this will help us provide an effective solution.
In the meantime, let's complete the troubleshooting steps below if you haven't performed them yet, as this will help the synchronization problem.
To begin with, let's manually update the bank connection within QuickBooks to refresh the connection between Monzo Bank:
- Go to the Transactions tab.
- Select Bank Transactions.
- Click on Refresh.

Please follow the on-screen steps to proceed with the update if you see a message.
Next, let's check your bank's website to see if there's system maintenance on their end:
- Kindly go to your bank's website.
- If you're unsure what URL to use, you can find it by going to the Bank Transactions tab and selecting the Link account.

- Search for your specific bank, then select it.
- Copy the listed URL, then sign in to your bank's website.
If you can log in, it means there aren't any significant problems with the bank. We can check for any alerts, updates, or messages related to your account.
If everything looks fine, let's go back to QuickBooks and manually select the Refresh button again.
Lastly, let's update your bank info in QuickBooks if you have recently updated anything on your bank's website, such as your account number, username, or password:
- Go to the Transactions, then select Bank Transactions.
- Select the tile for your Monzo business account.
- Click on the pencil icon and select Edit account info or Edit sign-in info.

- Make the necessary changes.
- Start a manual update again.
However, if the transactions and balances still don't sync, I suggest manually uploading bank transactions from your bank. Please follow the step-by-step guidance in the section For customers using the QuickBooks Sole Trader.
Additionally, please be aware that once the connection issue between your bank and QuickBooks is resolved, a duplicate transaction may occur due to manual uploads. I recommend excluding these duplicate transactions in the Transactions tab to maintain accuracy.
Furthermore, let's organize your bank transactions by assigning them to the appropriate categories. This will help to accurately represent your income and expenses.
We prioritize ensuring that your banking experience is seamless, and we take full responsibility for any issues that may arise. The Community is always here to support and assist you in every way possible.