3433348 - Direct Connect cannot connect to the Mainframe: NETWORK ERROR: SYBTCP ERROR INFO:, Request(Connect),SubFunc(Failed)

• DirectConnect fails connect to the mainframe via ISQL.
• DC Log shows:
  LogNotice    02/15/2024 08:42:55.569    [DCServerName]    11    [USERID]   isql    NETWORK ERROR: SYBTCP ERROR INFO:, Request(Connect),SubFunc(Failed), Request(Connect),SubFunc(Failed), SYBTCP RetCode(1) Description(SYBTCP_FAIL), TCP API RetCode (0) Description(Unknown WINSOCK Err Code) errmsg[Win NT system call sybtcp_connect: read(REPLYBUF), error num 0, tranaction AMD2, region name [CICS REG], host name BIGIRON.WDF.SAP.CORP, port num 8062 ]
  LogClientMessages    02/15/2024 08:42:55.579   [DCServerName]   11   [USERID]    isql    Error: 30261 Severity: 10 TCPIP Network Error: { [NOTCONNECTED] Lost connection to database, , Request(Connect),SubFunc(Failed), SYBTCP RetCode(1) Description(SYBTCP_FAIL), TCP API RetCode (0) Description(Unknown WINSOCK Err Code) } <HostName=bigiron.wdf.sap.corp>, <PortNumber=8062>, <Region Name=[CICS REG]>, <TPName=AMD2>
  LogClientLogin    02/15/2024 08:42:55.590   [DCServerName]     11  [USERID]    isql    ...Connection refused by service library 'DB2'.
• CICS Message User log shows:
  SYBASE LISTENER SYA1 SYBTP12 - COULD NOT START HANDLER
                       EIBFN = 1008 EIBRCODE = 040000000000 EIBRSRCE = SYGH     EIBRESP =       17 EIBRESP2 =        0
  
  

• Mainframe Connect 15.0 Sp06
• Direct Connect 15.0.1 

DC  ISQL IOERR TSQ SYGH , KBA , BC-SYB-MFC , Mainframe Connect (MFC) , Problem