Inst. Group: Reversal of doc.no. &1 (doc. no. &2 for PI) ended with error

What causes this issue?

The document you want to reverse (document &V1&) belongs to an
installation group. It is connected to the <DS:DE.MAINDOCNO>primary
installation document</> &V2&.
In this case, the complete installation group, that is, all documents
connected to primary installation document &V2&, and document &V2&
itself, if necessary, must be reversed together.
However, an error occurred during the reversal of document &V1&. As a
result, the installation group cannot be reversed.

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?

Correct the error in document &V1& and start the reversal again.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.