The vCenter Server authentication services use syslog for logging. You can examine the log files to determine the reasons for failures.

Table 1. vCenter Server Authentication Services Logs
Service Description
VMware Directory Service By default, vmdir logging goes to /var/log/messages or /var/log/vmware/vmdird/.

For issues at deployment time, /var/log/vmware/vmdir/vmafdvmdirclient.log might also contain useful troubleshooting data.

VMware Single Sign-On vCenter Single Sign-On logging goes to /var/log/vmware/sso/.
VMWare Certificate Authority (VMCA) VMCA service log is located in /var/log/vmware/vmcad/vmcad-syslog.log.
VMware Endpoint Certificate Store (VECS) VECS service log is located in /var/log/vmware/vmafdd/vmafdd-syslog.log.
VMware Lookup Service Lookup service log is located in /var/log/vmware/sso/lookupServer.log.