Aged debtor vs control account agrees as a whole but there is a difference between currencies

The most common cause is an 'any currency' customer account where a set of allocated transactions are in different currencies. For example, an invoice, payment, and account adjustment all allocated together, but one transaction is in a different currency:

In this example, the total on the customer account is zero, as is the combined total of the £ and EUR nominal accounts. However, when checking the currency accounts individually, there is a difference — because the £250 adjustment posted to the EUR control account. Both the £ and EUR accounts are out against the debtors for the same currency. To resolve this, either reverse the affected transactions and re-enter them correctly, or use the Corrections module to update the transaction details (if you have access to it). If you are unsure which transactions caused the difference, contact support. See Get support in Dimensions.