Resolve updating preview images on questionnaires in Visual Dialogue keeps UpdateSystemObjectThumbnail task in status 'Processing'



When updating preview images on questionnaires, the UpdateSystemObjectThumbnail task in Dialogue Admin permanently shows as a status of Processing.
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The problem happens when the Portrait Dialogue (PD) application and/or web servers have their Internet Explorer security settings set to restrict the web sites that they can display. This may be as a result of a high security Group Policy.
The issue (and its resolution) also applies to other PD web sites that appear to be restricted on the web server.

To test this, launch Internet Explorer on one of the Portrait Dialogue servers and attempt to navigate to an example Questionnaire Preview Page. The URL will take the following format:

[QuestPreviewUrl]/Preview.aspx?Session=[Session Key]@[Instance name]&QuestionnaireID=[Questionnaire ID]&LayoutIndex=[Layout index]&PageIndex=[Page index]&ForceFetch=true

The sections in brackets can be substituted as follows:

1. QuestPreviewUrl: This is the value of the QuestPreviewURL found in Dialogue Admin.
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2. Session Key: Log on through the DialogServerAPI web application to get the session key. You can use the SystemAPI Login or WindowsAuthenticationAPI Login method.
The SessionKey can be found from:
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then 'Login':
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As above, Login takes a number of parameters as shown below.
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Clicking the 'Invoke' button results in the following output (including an example of the generated session key)
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3. Instance name: Your PD instance name
4. Questionnaire ID: Any one of your Questionnaire IDs
5. Layout index: The questionnaire layout to use. If the questionnaire doesn’t have a layout, it should be set to -1, otherwise it should be set to 0 to use the first layout.
6. Page index: The page to use in the preview. Zero based, you should specify the first page which is not a welcome page (typically 1). Set to 0 if no layout is used.

When the generated URL is tested, if there is a pop-up message saying that the site was blocked, continue on to the resolution section.


UPDATED: April 21, 2017
Open Dialog Admin and navigate to the General admin | Parameter collections section. Make a note of all of the Public URLs and Internal URLs.
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On each of the PD application servers and/or web servers, log on as the domain user running the MH services and open the Internet Explorer Options dialog.
Select the Security tab.
Click on the 'Trusted sites' zone and then click the Sites button.
Deselect the checkbox about requiring https and add the stem name(s) of your Public URLs and Internal URLs (e.g. http://MyPdServer)
Click Close and click OK on the Internet Explorer Options dialog.
Recycle the Portrait Dialogue COM+ service.