how to general new system hook ?

1. I update gitlab-ee 11.4.5 to gitlab-ee 11.4.8. I lost gitlab-ee gitlab-secret.json old version. so gitlab dont read old pgsql webhook data. when i click system hook,the website happen 500.settings integrations of other project system is ok when I delete pgsql web_hooks table . But I want to know how to general new system hook data to pqsql.