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Upgrade to CMS version 10.3 gives me error while loading some pages in Edit mode



recently I have upgraded my application to CMS 10.3 hosted on Cloud. I am getting following error while loading couple of pages in edit mode.

Preview Unavailable

Failed to load the preview within the given time constraints.

In console Network tab it shows red for following:


Hope someone has solution on this. 

//Sanket Mahimkar

Dec 29, 2016 12:50

@Sanket, was this resolved by getting the correct CMS UI version? The issue you had in another post.

Edited, Jan 04, 2017 11:18
<p>Hi John,</p> <p></p> <p>Yes the issue with&nbsp;<a href="/forum/developer-forum/Problems-and-bugs/Thread-Container/2016/12/projectnotificationformatter-error-while-upgrading-cms-to-10-3/"></a></p> <p>Resolved. I am facing another issue, for some of the pages (I think which are heavy in content) in edit mode it gives&nbsp;</p> <h2>Preview Unavailable</h2> <p>error, it seems like timeout. I am not sure where it has that configuration.</p> <p></p> <p>Regards,</p> <p>Sanket Mahimkar</p>
Jan 04, 2017 11:27

What version did you have before the upgrade? We show that when the page takes too long to load, so if you try again does it eventually load or does it always time out?

Jan 04, 2017 14:08


I think the same that pages which are taking time to load, or in case when Internet connection is poor, gives this issue. I was using EPi version 9.12 before and I never has this issue. Infact on 9.12 version same page is getting loaded and 10.3.1 it is giving error.


Sanket Mahimkar

Jan 04, 2017 14:27

Is it CMS UI 10.3.1 or CMS Core 10.3.1? There's a CPU spike fix in Core 10.3.1 that might solve this.

Jan 04, 2017 15:01


Both CMS UI and Core are in 10.3.1. See below packages:

<package id="EPiServer.CMS" version="10.3.1" targetFramework="net45" />
<package id="EPiServer.CMS.Core" version="10.3.1" targetFramework="net45" />
<package id="EPiServer.CMS.UI" version="10.3.1" targetFramework="net45" />
<package id="EPiServer.CMS.UI.Core" version="10.3.1" targetFramework="net45" />

<package id="EPiServer.Framework" version="10.3.1" targetFramework="net45" />


Sanket Mahimkar

Jan 04, 2017 15:25


FYI, The application is hosted in Azure with EPiServer.Azure version Is there any configuration or something to increase the timeout period.


Sanket Mahimkar

Jan 04, 2017 15:27

Hi Sanket and sorry for not answering this sooner. There is a appSetting for this timeout that you can set. The default value is 15 seconds.

    <!-- Set iframe timeout to 20 seconds -->
    <add key="episerver:ui:PreviewTimeout" value="20000" />

You can find some more information about it here:

Jan 16, 2017 10:45

...or maybe fix the slow pages? :)

Jan 16, 2017 11:12
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