Please ensure you've a public and published plan that on the Content integration tab is protecting your article, its category, or its section. Once done please navigate to CBSubs > Settings > Integrations and on the Content/Extension tab ensure it is configured to hide Readmore content only. Please also adjust the usergroups that ignore this protection while there (if logged in as a Super Administrator articles will function as normal!). I also recommend upgrading to CB 1.4 when possible.