Reset: Document & does not exist

What causes this issue?

Document &V1& in controlling area &V2& is to be reversed. However, this
document is not in the data bank.

System Response

The reversal is terminated.

How to fix this error?

Please inform your system administrator. There is a discrepancy between
document file COBK and allocation document file T811D.

Error message extract from SAP system. Copyright SAP SE.