Fixing the Famous 503 Service Unavailable (Failed to connect to Endpoint) Error When Trying to Connect to vCenter Web Portal

If you are using VMware’s vCenter to manage your virtualization environment, the chances that you encounter this famous 503 Service Unavailable message are pretty high.

503 Service Unavailable (Failed to connect to endpoint: [N7Vmacore4Http20NamedPipeServiceSpecE:0x00007fd8c00155b0] _serverNamespace = / action = Allow _pipeName =/var/run/vmware/vpxd-webserver-pipe)

Most of the time, a restart would get you going again. But today, a simple restart won’t cut it. I had to try a few different ways to finally get the login page again.

First of all, if SSH isn’t an option, you will need to get access to the console, which mostly you can through the ESXi server management portal.

Press Alt+F1 to get to the login screen and use root user to log in. I hope you still remember your root password. If not, check this one out. Once logged in, launch shell, by

shell.set --enabled true

Then, run the following to check the services status.

service-control --status --all

If you see any stopped services, run the following to start all services.

service-control --start --all

Then wait for another 15 minutes before checking the web portal again.

While you are in the console, you should also check and make sure none of the logical drives should be full.

df -h

A few other resources to look at if the above doesn’t help.

  • Reindex the database –
  • VMware KB –
  • Due to the vSphere web client –
  • Due to the corrupted certificate store –

/Updated on Oct. 23, 2022/

To fix the issue due to the corrupted certificate store,

Download the script attached to the VMware KB, and transfer the file to the vCenter Server via the tool WinSCP. You may need to follow this first.

Then run the script.

First, grant the script execution permission.

chmod +x

Then, run the script.


However, if you got the error message saying no such file or directory, run this first and try again.

sed -i -e 's/\r$//'

It could take a quite long time to see any results from the script. When it is finished, it should stop and restart the vmafdd service again.

Then, restart all the services of the VCSA.

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