If you see the alert displayed below, it means that a discrepancy has arisen between the balance and the sum of transactions in one of your connections.
By clicking on Show connections, you will see the misaligned connection, which you can correct by clicking on Open troubleshooting wizard.
This alert is visible also on Connections page. The image below shows an example.
To learn more and know the different methods available to correct the error, visit this link: