If not all of the calendar services started when you issued start-cal, the ones that did start must be stopped before restarting. For example, if enpd, csnotifyd, and csadmind started, but not cshttpd, then enpd, csnotifyd, and csadmind must be stopped.
To start calendar services:
Log in as a user who has administrative rights to the system where Calendar Server is running.
Use start-cal to stop and then restart services. For example:
start-cal issues a stop-cal command first before starting the various calendar services.
If stop-cal fails to stop, there might be some child processes that failed to stop. To handle this, see Fixing stop-cal Problems.