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
Go to Chrome -> preferences -> privacy and security -> cookies and other site data.
Or, go to chrome://settings/cookies.
Enter the site [*.]pageproofusercontent.com and click add.
To update cookie settings in Firefox
Go to Firefox -> preferences -> privacy & security.
In the cookies and site data section, click manage exceptions...
Add https://pageproofusercontent.com and click allow.
Click save changes.