Converting HTML / web pages returns an empty PDF

When you get a blank PDF when carrying out an HTML conversion then the most likely problem is that the account the Muhimbi Conversion Service runs under has no access to the page you are trying to convert. The easiest way to troubleshoot this is as follows:

  1. Launch our diagnostics tool from the Windows Start Menu.
  2. Navigate to the ‘HTML Conversion’ tab and click both ‘Convert’ buttons using the default settings. Each should return valid content.
  3. If both indeed return valid content then please change the URL to the URL of the content you are trying to convert. Please do not enter a username and password.
  4. If step #3 returns an empty PDF then look in your web server's (IIS) log file to see what the status code is.
 

When troubleshooting HTML Conversion take the following into account:

  1. All Internet Explorer settings, as configured for the account the Conversion Service is running under, are used during conversion. This includes security zones and other security related settings such as block lists, proxy settings etc.
  2. The actual conversion is carried out by the Conversion Service on the machine that is running this service. If the URL to convert is located on a different machine, or the IP address of the page to convert will cause the request to be routed 'off machine' then the request may go via various systems in your infrastructure, including (transparent) proxy servers, firewalls, authentication systems etc.
 
A common problem is that, even though the Conversion Service account has the appropriate privileges on the destination URL, authentication information is not automatically forwarded. This can be solved as follows:
  1. Log in to the desktop of the server that runs the Conversion Service using the account that the Conversion Service runs under.
  2. Launch Internet Explorer and navigate to Internet Options / Security.
  3. Select the zone for the domain of the URL that you are trying to convert. If the domain is not part of any zones then add it to the list of Intranet or Trusted sites.
  4. With the relevant zone selected click 'Custom Level' and scroll all the way to the bottom.
  5. Set 'Logon' to any of the Automatic options.
 
Determining the active Zone for a URL can be surprisingly complicated. Microsoft's IEZoneAnalyzer is a particularly useful utility for troubleshooting Zone settings. 


As of version 7.0 the credentials used for converting HTML to PDF is not limited to just the Conversion Service account. The credentials can be overridden in the Conversion Service's config file. Please note that Internet Explorer needs to be set to "User Authentication / Prompt for Username & Password" for the Account the conversion service runs under and for the Security Zone the web page is located in. 
  
<add key="HTMLConverterFullFidelity.URLUsername" value=""/>
<add key="HTMLConverterFullFidelity.URLPassword" value=""/>

 

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