Hi folks, my vCenter is installed on Windows Server 2012
-I can connect via my web browser through the https://[IP]:9443/vsphere-client
it works for the first time when I shutdown my Server then power it up again I get this page
I disabled firewall on my Server and on my Host also turned off my Anti-Virus
Sorry for ask, but are the vCenter services (including the Web Client) started? If not, see how to start them: How to stop, start, or restart vCenter Server services (1003895) | VMware KB
Many thanks to you friend , I think services was running unfortunately I'm re-installing my Server again and that is bad to me whatever I'll use my IP directly to acces vCenter via Browser and will not use DNS ( FQDN ) and that will not affect negatively the process, Right am I ?
I will recommend you have DNS working before install your vCenter, see the requirements: vSphere DNS Requirements
You install or upgrade vCenter Server, like any other network server, on a host machine with a fixed IP address and well-known DNS name, so that clients can reliably access the service.
Assign a static IP address and host name to the Windows server that will host the vCenter Server system. This IP address must have a valid (internal) domain name system (DNS) registration. When you install vCenter Server and the Platform Services Controller, you must provide the fully qualified domain name (FQDN) or the static IP of the host machine on which you are performing the install or upgrade. The recommendation is to use the FQDN.
When you deploy the vCenter Server Appliance, you can assign a static IP to the appliance. This way, you ensure that in case of system restart, the IP address of the vCenter Server Appliance remains the same.
Ensure that DNS reverse lookup returns an FQDN when queried with the IP address of the host machine on which vCenter Server is installed. When you install or upgrade vCenter Server, the installation or upgrade of the Web server component that supports the vSphere Web Client fails if the installer cannot look up the fully qualified domain name of the vCenter Server host machine from its IP address. Reverse lookup is implemented using PTR records.
If you use DHCP instead of a static IP address for vCenter Server, make sure that the vCenter Server computer name is updated in the domain name service (DNS). If you can ping the computer name, the name is updated in DNS.
Ensure that the ESXi host management interface has a valid DNS resolution from the vCenter Server and all vSphere Web Client instances. Ensure that thevCenter Server has a valid DNS resolution from all ESXi hosts and all vSphere Web Clients.