Oracle Message PGA-21210 - unable to open connection with SNA services

ERRORunable to open connection with SNA services
CAUSEThe RRM was unable to initialize its connection 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.