We are currently experiencing some issues with the Web CMS meaning that users cannot save/approve or preview content. We are working with our CMS provider, TerminalFour, to get these issues resolved as soon as possible.
To avoid losing work, we would recommend that you do not use the CMS until we're confident the underlying issue has been resolved. We will provide updates in the #web-cms-users Slack channel, and email again once the system is back up and running properly.