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Why is my content not loading and why am I seeing a message about a proxy server?

The problem is usually caused by a proxy server or firewall that interrupts the communication between the content and the authentication server.

To resolve this issue, ask your IT department to whitelist the domain on port 443 (https). The domain may differ for different users so be sure to check which domain the content is delivered from, however, it may be one of these:    

Why do proxy servers or firewalls block the content? 

Proxy servers and firewalls are designed to protect your organization from unwanted viruses, malware and other phishing type schemes. However, some types of communication is safe, such as the content you're trying to access as this is coming from a legitimate and trusted source.

How do I make these changes?

You need to speak to your IT admin as they'll know what to do but here are some quick tips:

  1. For proxy or firewall configurations, your IT person must ALLOW direct communication with the domain that the content is being sent from on port 443 - the domain might be or or the domain of the customer who sent the link to the file
  2. For Adobe Reader/Acrobat configurations, follow these steps: 
    • Open the Adobe Reader or Acrobat program
    • From the top men, select Edit > Preferences
    • Under Categories, click Trust Manager
    • Click the change Settings button
    • Add the applicable domain to the "Allow communication" section 

How can I check for a proxy server:

  1. Click on the Start Menu and open Settings
  2. Select Network & Internet > Proxy
  3. Under Manual proxy setup, check to see if the "Use a proxy server" box is selected

What error message does the user see in Adobe Reader or Acrobat?

They would see a pop-up message like this: 

Error Message


How do I fix distorted images in the Web Viewer?

Navigate to the Vitrium dashboard and go to Settings > Content Settings > Advanced Options. Ensure the feature 'Disable Image Optimization in Web Viewer' is enabled.

Screenshot 2023-03-07 at 2.59.47 PM

After doing this, refresh the content. If there is no discernible improvement please follow the instructions below to continue troubleshooting. 

If you are using Google Chrome, Firefox, Safari or Microsoft Edge navigate to this page for instructions on how to disable hardware acceleration in your browser.

If you have uploaded a PDF file to Vitrium and the images in the web viewer appear distorted, grainy, or have lost some of their original quality compared to the original file, then you may be able to resolve this by optimizing the original PDF file in Adobe.

Try Adobe's built-in optimization tool in Adobe Acrobat and refer to the following screenshots for our recommended settings.

Alternatively, if you use Adobe InDesign to create your PDF content, click here to review our suggested PDF Export Settings in Adobe InDesign.

Recommended Settings in PDF Optimizer in Adobe Acrobat

Open Adobe Acrobat and navigate to Tools > Optimize PDF. Change the Settings to Custom and update the image settings:

Screenshot 2023-03-07 at 4.03.43 PM

Navigate to fonts and ensure 'Do not embed any font' is checked.

Screenshot 2023-03-07 at 4.01.03 PM

Navigate to Transparency and select medium resolution first. If the conversion fails, revert to high:

Screenshot 2023-03-07 at 4.06.03 PM

Navigate to Discard Objects:

Screenshot 2023-03-07 at 4.07.43 PM

Navigate to Discard User Data and ensure the following is correct:

Screenshot 2023-03-07 at 4.09.13 PM

Finally navigate to Clean up:

Screenshot 2023-03-07 at 4.10.39 PM

If you tried these settings and it still did not help resolve the distorted images, then please submit a ticket to the Vitrium team and include your original PDF file and a screenshot of the distorted image, if possible.