Correspondence locked for print

What causes this issue?

The correspondence request with correspondence key &V1& and
correspondence type &V2& is locked for printing.

System Response

The correspondence request is not printed.

How to fix this error?

The correspondence request can be printed as soon as the application has
removed the lock.

Procedure for System Administrators

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.