HTML5 vSphere Web Client error message

Kevin M
Kevin M used Ask the Experts™
Hi, we are running version 6.7.0 across the board and just today we are able to connect in using the VSphere Web Client (Flex), but not HTML5.

Error produced:
503 Service Unavailable (Failed to connect to endpoint: [class Vmacore::Http::LocalServiceSpec:0x0000004fa48f0390] _serverNamespace = /ui action = Allow _port = 5090)

When we log into the Flash enabled client, the options to restart the VMware vSphere Web Client are greyed out, even when logged in as local admin (see attached).
This article suggests changing the web client timeout, but I am reluctant to do that as it was working fine before.

Is that what needs to be done here, and if so, where is the file on a Windows Server 2012 R2 box running vCenter?

Any help would be mich appreciated. Thanks.
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VMware and Virtualization Consultant
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Expert of the Year 2017
As for the issue, Restarting Network Management services or host restart and check if you still have the same issue.

see here for the documentation to change it
Kevin MSystems Engineer


Thanks,  we were having difficulties finding that file on the 2012 server. I found it, but getting Access denied when changing the session.timeout value, which was commented out.

That being said, I restarted the service using the followingL
C:\Program Files\VMware\vCenter Server\bin\service-control --stop vsphere-ui
C:\Program Files\VMware\vCenter Server\bin\service-control --start vsphere-ui

After thinking about it for a minute the HTML5 client is back up.
Thanks for your quick response, and I'll still look to change that value.
Andrew Hancock (VMware vExpert / EE Fellow)VMware and Virtualization Consultant
Fellow 2018
Expert of the Year 2017

Make sure you are a local administrator, services are stopped, and using a Administrative command prompt.

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