Error "503 Service Unavailable" when attempting to access vCenter Server vSphere Client
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Error "503 Service Unavailable" when attempting to access vCenter Server vSphere Client

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Article ID: 337535

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Updated On:

Products

VMware vCenter Server

Issue/Introduction

  • Logging in to the vCenter Server using the vSphere Client fails.
  • Errors may appear as:

    503 Service Unavailable.

    503 Service Unavailable (Failed to connect to endpoint: [N7Vmacore4Http20NamedPipeServiceSpecE:0x00007fb7d00200a0] _serverNamespace = / action = Allow _pipeName =/var/run/vmware/vpxd-webserver-pipe)

Environment

VMware vCenter Server

Cause

This issue may occur due to a number of reasons such as:

  • The vCenter Server currently down because of maintenance.
  • The reverse Proxy service on vCenter Server is down.
  • The vSphere web client service is down.
  • Mis-configured Firewall settings.

Resolution

Before troubleshooting, it is critical to understand what a "503 Service Unavailable" error is. For more insights, see List of HTTP Status Codes.

A 503 Service Unavailable error is an HTTP response status code that indicates that the server is temporarily unable to handle the request. 

There are also different looking 503 pages on other websites:

For example:

  • 503 Service Unavailable (Failed to connect to endpoint: [N7Vmacore4Http20NamedPipeServiceSpecE:0x00007fb7d00200a0] _serverNamespace = / action = Allow _pipeName =/var/run/vmware/vpxd-webserver-pipe)
  • 503 Error
  • Service Unavailable – DNS Failure
  • HTTP Error 503
  • HTTP 503
  • 503 Service Temporarily Available

An important thing to remember is that a 503 error is a server-side error. This means that the problem exists within the vCenter Server or website (server) the user is trying to access, and not the end user's computer (client).

Troubleshooting HTTP response status code "503" on the vSphere Web Client when connecting to the vCenter Server. 

  1. Try again in a few minutes.

    Note: It is most likely that the vCenter Server is just busy acknowledging the request. The vCenter server was able to process the request and was able to respond back with the "503 Service Unavailable" error. It is just not able to acknowledge the request either because it is busy with other tasks at the moment or it currently down with very limited services due to maintenance.
  2. Try again in a few minutes on a different client.
  3. Confirm the status of the VMware vCenter Services. Ensure all required services are up, running and functional. For more insights, see:
  1. Check if there are disk space issues on the vCenter Server.

    Notes: 

    Disk space issues can cause more than one service to shutdown which can result in the HTTP 503 Error Response Code.
    Disk space issues do not directly cause a 503 Error Response Code, but the services being down due to a failure causes the error.
  1. Check whether certificates are expired.
  1. Other causes of critical services being down can include:

    • Database server disconnected for Windows vCenter Server, due to:
      • database service account password change
      • network change
    • Database corruption
    • Machine account password problems
    • Very high storage communication latency
    • Very high virtual CPU contention
    • Time synchronization problems
      • between vCenter and PSC
      • between vCenter and database server
      • between vCenter and ESXi hosts
      • between vCenter and domain controllers
  2.  From the vCenter Server, investigate the vsphere_client_virgo.log file located at:
    • Windows vCenter Server - C:\ProgamData\VMware\vCenterServer\logs\vsphere-client\logs\
    • vCenter Server Appliance - /var/log/vmware/vsphere-client/logs/
  3. Also, look at the vpxd.log file located at:
    • Windows vCenter Server: C:\ProgramData\VMware\vCenterServer\logs\vmware-vpx
    • vCenter Server Appliance: /var/log/vmware/vpxd

Additional Information

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