Resolved: last night, the web hosting company for illustrativemathematics.org and illustrativemathematics.blog resolved an issue with their security feature that was preventing users from accessing those websites.

Update: the issue lies with a 3rd party service and we are awaiting for their teams to address the issue. Engineering is monitoring status updates and will notify the organization once we have more information.

We are aware the users are experiencing intermittent issues accessing the site due to a CloudFlare block warning. We are investigating and recommend that users re-try the site if they receive the error or clear their cache if the issues persists for them.

We are currently investigating this issue.