Check your allowed_iframes site setting and make sure the CodePen embed URL pattern is listed there.
Also verify that allowed_onebox_iframes isn’t too restrictive.
Finally, confirm that codepen.io isn’t included in blocked_onebox_domains.
Check your allowed_iframes site setting and make sure the CodePen embed URL pattern is listed there.
Also verify that allowed_onebox_iframes isn’t too restrictive.
Finally, confirm that codepen.io isn’t included in blocked_onebox_domains.