Allocation of main transactions not possible (Appl. &)

What causes this issue?

The allocation of transactions to internal transactions could not be
determined.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Maintain this allocation in table TFKIVV (allocation of internal
transactions to transactions) using view V_TFKIVV.

Error message extract from SAP system. Copyright SAP SE.