3137320 - Error during upgrade "Current step: Create kernel symbolic links"

• During the upgrade process of a Java Netweaver system from 7.0 to 7.5  error shown in Create kernel symbolic links Step
  
  CREATE-KERNEL-SYMLINK_10.0.LOG:
  Dec 27, 2021 3:22:16 PM [Info  ]: Process ID 1835, name sapcontrol has been started.
  Dec 27, 2021 3:22:16 PM [Info  ]:   Command line: /sapmnt/<SID>/exe/uc/hpia64/sapcontrol -nr 10 -host hlerpp01 -user <SID>adm <SecureField> -prot GSOAP_HTTP -function OSExecute /bin/sh -e /usr/sap/<SID>/SYS/global/sdtremote/link_kernel_dirs.sh 0 300
  Dec 27, 2021 3:22:16 PM [Info  ]:   Standard out: /usr/sap/<SID>/SUM/sdt/log/SUM/SAPCONTROL_OSEXECUTE_10_10.OUT
  Dec 27, 2021 3:22:16 PM [Info  ]: Process ID 1835 has been started.
  Dec 27, 2021 3:22:16 PM [Info  ]: Waiting for process ID 1835, name sapcontrol to finish.
  Dec 27, 2021 3:22:16 PM [Info  ]: Process ID 1835, name sapcontrol has been finished, exit code 1.
  Dec 27, 2021 3:22:16 PM [Error ]: The following problem has occurred during step execution: com.sap.sdt.util.diag.DiagException: Error while executing Task with input file ExecuteTasks.xml and task CREATE_KERNEL_LINK.
  Could not execute external process.
  Sapcontrol client could not perform action os process execute on instance null
  Return code condition success evaluated to false for process sapcontrol for action os process execute.
  
  
  
• SAPCONTROL_OSEXECUTE_10_04.OUT23.12.2021 19:00:02
  OSExecute
  FAIL: Connection refused, connect failed in tcp_connect()
  
  
  
• Other phases can be affected as well with the same symptom

Netweaver Java

FAIL: Connection refused, connect failed in tcp_connect(), sapstartsrv, sapcontrol has been finished, OSExecute , KBA , BC-UPG-TLS-TLJ , Upgrade tools for Java , BC-CST-STS , Startup Service , Problem