VSE 5.2 listener won't activate

Q:  

What causes these errors?    
MBCB171 SOCKET ERROR: RC(001) ERRNO(01127)     
EZY1293E INITAPI CALL FAILURE TRANSACTION=EZA1 TASKID= 0000035L ERRNO= 121  

A:

CSI APAR PI36463. 5.2 TCPADDR parameter in EZAC,DIS,CICS is now important. Set to 00.