We're aware of some connectivity issues for some portals, and are implementing a fix currently. Next update in 15 mins.
UPDATE 06:42: All portals available again, and we are monitoring. Next update in 15mins.
UPDATE 06:45: Issue resolved. We noticed around 15% of US-based traffic was unable to connect to portals, and have added a workaround for affected users. This affected mainly US-based users, and around around 1 in 6 requests. Apologies for the disruption.