I have added a zimbraPublicServiceHostname to the domain. In Zimbra Desktop die REST URLs of the Calendar share changed as expected.
But Not in the WebClient - which still shows the old REST URLs entries.
I have restarted the Zimbra services zmcontrol restart.
I have checked zmprov gd domain.com | grep Public and the entry is there and have added zimbraPublicServiceProtocol too.
Well - 90% of my users use the WebClient.
Any help is appreciated ....