That happer when you restart you vCenter Server and can not access your vSphere Client with notice “The vSphere Client web server is initializing” on web browser or other error like : 503 Service Unavailable (Failed to connect to endpoint [classV macore::Http::NamedPipeServiceSpec:0x000001ca2b132ba0] _serverNamespace = / action = Allow _pipeName =\.\pipe\vmware-vpxd-webserver-pipe)
All you need to do is…. Relax and waiting for 10-15 min (maybe – depent on your server system) – just drink a cup of coffee, listen music or view some youtube video or visit copir.net for nothing 😀 (just kidding)
This problem happen because vCenter Server acquire much more resource after restart, maybe only happen on low resource server like vmware server test lab like my system… vCenter Server need time to load all module and running normal.
So just wait and have a nice day.
Below some of screenshot of The vSphere Client web server is initializing and 503 Service Unavailable on vCenter Server after reboot.