Cannot logon to TPX when using TPXUSNSF to route users to different TPX started tasks

Document ID : KB000003975
Last Modified Date : 14/02/2018
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Issue:

TPX user exit TPXUSNSF routes users to a specific TPX started task. Users report that they cannot get logged on.

Environment:
CA TPX for z/OS
Resolution:

To debug this kind of logon problem:

  1. Look for any application errors, such as a CICS region being down unexpectedly and/or not accepting logons 

  2. Verify the VTAM startup parameter IOPURGE. 

    The VTAM startup parm IOPURGE is set to some number of seconds. After this number of seconds, VTAM will assume that no reply is coming back and will notify the requestor (in this case TPX) of the fact that this application could not be found.

    • If you have this value set at the default (zero) you will need to set this to a positive number. 

    • If you have it set for a value other than the default, then IBM will need to review why the IOPURGE is not working.

For example:

Initial TPX = TPX1 This TPX routes users to another TPX depending on logon id.

Routed to = TPX2 Has CICS error messages in it. 
(same LPAR)

Messages in initial TPX, TPX1:

      VTAM was issuing NSEXIT's - VTAM is telling TPX that the terminal went away
 
      TPXL0152 07/25/08.207 13:59:58.34 NSEXIT RU: NOTIFY  PLU: NTPXES   SLU: NTV1  0EA6 13AE9538                                                                 
      EVENT IGNORED, VTAM PASSED AN INVALID PARAMETER        

Messages in TPX2:

      TPXL0085 07/25/08.207 16:54:43.11 RPL ERROR MANAGEMENT ROUTINE ENTERED        
      PLU=NTV105A3  SLU=NXVUU003  USER=PETE155  REQ=29 00001024 00800000            
      TO APPL                                                                       
            TERMSB=13D123E0 APPLSB=13D03C50 EB=13666200 RPL=136C0608                
            RTNCD=10 FDBK2=12 MEANING=MACRO FAILURE, SENSE INCLUDED                 
            SENSE CODE=087D0001 MEANING=LU UNAVAILABLE      
                        
       Sense code 087D                                                              
       Session services path error: A session-services request cannot be rerouted   
        along a path of SSCP-SSCP sessions. This capability is required, for        
        example, to set up a cross-network LU-LU session.                           
      0001      An SSCP has attempted unsuccessfully to reroute a session           
                services request to its destination via one or more adjacent        
                SSCPs; this value is sent by a gateway SSCP or a nongateway SSCP    
                when it has exhausted trial-and-error rerouting.

It appears that VTAM was having some problems that lead to users not being able to logon