Insert of object R3TR &1 &2 into transport request is cancelled.

What causes this issue?

The Proxy object for each logical transport object must exist in the
transport request.

System Response

Insert of Proxy objects into transport request is cancelled.

How to fix this error?

Try to execute the report ' SPROX_LOG_TRANSP_OBJ_INSERT' again or add
the object to the transport request manually as following:
Program ID is fixed: 'R3TR'.
Object Type: '&V1&'.
Object Name: '&V2&'.

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.