Due to frozen the ESXi 6.0 server , we restarted the Management agent services by the following command by reference of https://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1003490

/etc/init.d/hostd restart  -- not worked

/etc/init.d/vpxa restart  -- not worked

finally we restated this service   services.sh restart -- its take to long time and after onward we are unable to login into the Vsphere by client and webclient also get the following error

vSphere client: vSphere Client could not Connect to IP. An Unknow connection error occured.(The server could not interpret the clients request.( The remote server returned an error: (503) Server Unavailable)

WebClient:

503 Service Unavailable (Failed to connect to endpoint: [N7Vmacore4Http16LocalServiceSpecE:0x1f08c898] _serverNamespace = / _isRedirect = false _port = 8309)

All the VM in this HOST are UP and Running without any issues with the network connection.

We are able to connect the SSH with the Management IP Address. 

Can someone HELP ME ASAP.