VTAM® issues this message as the first in a group of messages when a UNIX System Services function call issued by the SNA Network Management Server fails, which causes the Server to close a connection with a client application. The SNA Network Management Server is still able to accept client connection requests, and other existing connections are not disrupted.

IST1933I   SNAMGMT SERVER CLOSING CONNECTION TO userid      
IST1927I   SOCKET callname CALL FAILED - RC = rtncode RSN = reason
IST314I    END  

IST1933I

• This message indicates that the SNA Network Management Server is closing a connection with a client application owned by userid.
• userid is the user ID that owns the client application whose connection is being closed. If the user ID is unknown, VTAM displays ***NA***.

IST1927I

• callname is the name of the UNIX System Services function call that failed. These functions are listed and described in the z/OS UNIX System Services Programming: Assembler Callable Services Reference.
• rtncode is the return code value, in decimal, from the UNIX System Services function call that failed. These return codes are listed and described in the z/OS UNIX System Services Messages and Codes.
• reason is the reason code value, in hexadecimal, from the UNIX System Services function call that failed. The format of the 4-byte reason code is explained in the introduction to the Reason Code section of the z/OS UNIX System Services Messages and Codes, where the reason codes are listed.