Message type: E = Error
Message class:  TU - Billing/Scheduling/Budget Billing 
Message number: 752
Message text: Item for due date &1 cannot be unlocked because payment was made
You cannot unlock the item for due date &V1& because a payment was
already made for at least one of the contracts.
The system issues an error message and will not allow you to continue with this transaction until the error is resolved.
Error message extract from SAP system. Copyright SAP SE.
The SAP error message TU752 indicates that an item cannot be unlocked because a payment has already been made against it. This typically occurs in the context of financial transactions, such as accounts receivable or accounts payable, where a payment has been processed, and the system prevents further changes to ensure data integrity.
Cause: Payment Processed: The primary cause of this error is that a payment has already been recorded for the item in question. This means that the financial transaction is finalized, and the system does not allow modifications that could affect the accounting records. Document Status: The document associated with the item may be in a status that does not allow for unlocking or changes due to the payment being processed. Configuration Settings: Certain configuration settings in SAP may restrict changes to documents that have been paid.
Solution: Review Payment Status: Check the payment status of the item. If a payment has been made,
 Get instant SAP help. Sign up for our Free Essentials Plan.
Get instant SAP help. Sign up for our Free Essentials Plan. 
TU751 Item for due date &1 cannot be unlocked because it was already stopped
What causes this issue?  You cannot unlock the item for due date &V1& because it was already stopped in at least one of the contracts.System R...
TU750 Items could not be unlocked because BB plan was already deactivated
What causes this issue?  You cannot unlock any due dates because the budget billing plan has been deactivated.System Response  The system issues an er...
TU753 Item for due date &1 cannot be unlocked
What causes this issue?  You cannot unlock items of a budget billing plan that are part of an installment plan.System Response  The system issues an e...
TU754 Item for due date &1 cannot be unblocked because it was already dunned
What causes this issue?  You cannot unlock the item for due date &V1& because it was already dunned in at least one of the contracts.System Re...
Click on this link to search all SAP messages.