If you can’t open a website or HTML proof it is possible that your browser’s cookie settings are the cause. Follow the below instructions to add a custom behaviour/exception to your browser’s cookie settings.
To update cookie settings in Chrome
Step 1
Go to Chrome -> preferences -> privacy and security -> cookies and other site data.
Or, go to chrome://settings/cookies.

Step 2
In the customized behaviours section, for sites that can always use cookies click add.

Step 3
Enter the site [*.]pageproofusercontent.com and click add.

To update cookie settings in Firefox
Step 1
Go to Firefox -> preferences -> privacy & security.
Step 2
In the cookies and site data section, click manage exceptions...

Step 3
Add https://pageproofusercontent.com and click allow.

Step 4
Click save changes.
