TPX - CICS session start fails. Observe VTAM SENSE CODE=0857xxxx in the TPX LOG

Products

• TPX - Session Management

Issue/Introduction

TPX session start for CICS regions fails.  After recycled TPX all return back to normal.
VTAM  SENSE CODE=08570002 and 08570003 are observed (multiple times) in the TPX LOG.
A TPX recycle was needed to clear the error.

03/17/21.076 08:07:18.29 ACB TG782200 SELECTED FOR USER USER01  APPL CICSXXX
03/17/21.076 08:07:18.30 RPL ERROR MANAGEMENT ROUTINE ENTERED              
PLU=TCPIP878  SLU=TG782200  USER=USER01  REQ=29 00001024 00800000 TO APPL 
 TERMSB=16ED2490 APPLSB=16EF13C0 EB=169DB200 RPL=169BC588                  
 RTNCD=10 FDBK2=12 MEANING=MACRO FAILURE, SENSE INCLUDED                   
 SENSE CODE=08570003 MEANING=SSCP - LU SESSION NOT ACTIVE                  

Environment

Release : 5.4
Component : CA-TPX for Z/OS

Resolution

Here, TPX is a victim rather than the cause.
Verify you are current on TPX maintenance in order to avoid any defects that have already been fixed. 

The TPX LOG displays multiple VTAM sense code 08570002 and 08570003.

Description 08570002 
 
SSCP-LU Session Not Active: The SSCP-LU session, required for the processing    
of a request, is not active; for example, in processing REQECHO, the SSCP did   
not have an active session with the target LU named in the REQECHO RU. 

      0002 
          The SSCP-PLU session is inactive.   
          VTAM hint: For a USERVAR, an APPL or CDRSC definition with the same  
          name as the USERVAR was found and was not active.                    

**  Observed  Virtual Terminal being acquired multiple times. successively and appears to have been hung in VTAM. 

Description  08570003 
 
SSCP-LU Session Not Active: The SSCP-LU session, required for the processing   
of a request, is not active; for example, in processing REQECHO, the SSCP did  
not have an active session with the target LU named in the REQECHO RU.         
 
     0003 
         The SSCP-SLU session is inactive.                                 
         VTAM hint: For independent logical units, the independent logical 
         unit is inactive.   

**  Observed  Virtual Terminal being acquired multiple times. successively and appears to have been hung in VTAM.

If the CICS applications are in a cross domain environment, review CDRS setup.
Missing or incorrect setup has been known to cause failures generating the 0857 sense codes. 

One option to circumvent this without recycling TPX is to inactivate the offending virtual terminal using TPXOPER.

    MOD VT=vtermid,{AVAIL|UNAVAIL}             
    allows you to specify whether the designated virtual terminal is available/unavailable for selection.      

This will enable TPX to continue, sequentially assigning,  the next available VT. However, this is not a solution.
Recommend reviewing the CICS and VTAM logs to identify the cause and then fix it.