Message Oracle PGA-21211 - unable to allocate LU6.2 listen for RRM TP

ERRORunable to allocate LU6.2 listen for RRM TP
CAUSEThe RRM was unable to allocate an LU6.2 listen with the SNA software for LU6.2 communications. An OS-specific error message precedes this message.
ACTIONCheck the error information in the OS-specific error message to determine the cause of the problem, and take corrective action. Once the problem has been corrected, restart the RRM.