LU-LU session initiation does not complete

Problem statement
The LU-LU session activation begins but does not complete, and the session status is PRTPSTR.
Common symptoms
The LU-LU session activation begins, but message IST874I indicates that the session status is PRTPSTR.
Probable cause
The RTP connection between the session partner nodes has not fully activated.
User response
Specify the IOPURGE VTAM® start option to clear waiting signals.