ESX 4.0 503 Service Unavailable Web Error

I just rebooted one of our ESX 4.0 servers for maintenance reason, and after the server came back from the reboot I was getting this fat error when trying to connect to it using the vSphere  client:

vSphere client could not connect to “esxserver” the server could not interpret the communication from the client. ( the remote server returned an error: (503) server unavailable. )


going to the URL indicated on the ESX console gave me the same error as well…

the first thing I did was to the check the web status at the console with this command:

Service Vmware –webAccess status

I noticed the web service was stopped, so I started it by executing this command:

Service Vmware –webAccess start

tried to connect using vSphere, and nope, still got the error.

The Solution

do nothing! wait around 20 minutes, you will be able to login to the server after that. somehow if the DNS numbers are wrong in the ESX server, it will take that long to come back. obviously that is far too long to wait if you have some production VMs to bring up, but if you are reading this post because you have the problem, then most likely 20 minutes already went by…

correct your DNS numbers though.

you find that under Configuration > DNS and Routing on your ESX host:


Next time when you reboot the ESX server, the management console should come up right up.

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Hi there, thanks for visiting My name is Nelson Amaya, and I work in IT. I created this site with the intention of helping IT professionals in their IT job. I post tutorials about Linux, Windows, Open Source software, and many other emerging technologies. thanks for stopping by.