3455492 - DTP fails with error: 'Request &1 is already being processed'

When running DTP, the message is displayed: "Task &1 was scheduled but could not get any status. Check ODQ_TQ_MONITOR"

In DTP monitor, the DTP fails with error: 

Request &1 is already being processed
Veto from method CHECK_START_REQUEST_PROCESSING of class \CLASS=CL_RSBK_DTP_H. Request status will be changed. IOBJ &1 320 E RSBK CHECK_START_REQUEST_PROCESSING \CLASS=CL_RSBK_DTP_H
Locking of process &1 was refused by external tool (e.g. DTP) IOBJ &2 105 E RSPM &3
Operation  could not be carried out for IOBJ &1 120 E RS_EXCEPTION
Exception CX_RS_FAILED logged IOBJ &1 228 E RSBK CX_RS_FAILED

SAP BW/4HANA 

Request, is already being processed, Veto, CHECK_START_REQUEST_PROCESSING, Locking of process, was refused by external tool, ODQ_TQ_MONITOR , KBA , BW4-DM-DTP , ABAP Orchestration of Data Transfer Process , Problem