The problem is usually caused by proxy / firewall that interrupts the communication between the web viewer content (or Adobe program) and the authentication server.

To resolve this issue, ask your IT department to whitelist the domain protectedpdf.com on port 443 (https).  

If the customer who sent you the content is using their company domain (i.e. view.companydomain.com), then ask your IT department to whitelist that domain on the same port 443 (https).

For customers on our Canadian server, you will need to ask the  IT department to whitelist the domain vitrium.com on port 443 (https).

Why proxy servers affect the process:

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

Proxy server required configuration changes:

1. The proxy must ALLOW direct communication
   • With the DNS address api.protectedpdf.com and docs-ca.vitrium.com
   • On ports 443

Firewall required configuration changes:

1. Remove any blocks in Norton or other firewall software for
   • https://api.protectedpdf.com/
   • https://docs-ca.vitrium.com/
2. The firewall must ALLOW communication with
   • https://api.protectedpdf.com/
   • https://docs-ca.vitrium.com/

Adobe Reader/Acrobat Trust Manager configuration changes:

1. Open Adobe Reader/Acrobat
2. From the top menu bar, select Edit > Preferences
3. Under Categories, click Trust Manager
4. Click the Change Settings button
5. Remove any blocks to https://api.protectedpdf.com/ or https://docs-ca.vitrium.com/
6. Allow communication with https://api.protectedpdf.com/ or https://docs-ca.vitrium.com/

How to 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

Special consideration:

• Content providers have the option to use their own domain name. In those cases, you should contact your content provider and whitelist their domain name instead.

Adobe Reader/Acrobat screenshot