To restart VMware management agents, log onto the console of the ESXi server and go into Troubleshooting Options, then go into Restart Management Agents and hit OK.
Restarting VMware management agents is useful if the ESXi server cannot be managed from the vSphere client. If this doesn’t fix your problem you can restart the VMware services.
How To Restart VMware Services in ESXi
To restart VMware ESXi services you must connect to the ESXi host via an SSH program like Putty and run the following command: