When viewing a Payment (either in the billing tab of a project or in the Client Activity report) you will notice a "Settled" column. A green check here means this payment activity was transferred to your external bank account.

To view more information on this payment, you can click the drop down arrow to expand the payment. Here, you can view the "Settlement Status" and "Settlement ID".

The Settlement Status will show whether a transfer of this payment was successful or failed. The Settlement ID will match the "Received Credit" activity this payment is associated with, which can be viewed under your "Company Activity" report.