There is a issue affecting all UK Marketplace applications, this includes QuestionWhere, MyNearest, Markr and Sweet, which seems to have been introduced by yesterday’s ArcGIS On the web update.
The issue benefits in the applications not loading.
Esri UK are investigating the issue as a priority and operating straight with Esri Inc to get the dilemma resolved as soon as achievable.
The dilemma has now been resolved and all applications should be operating as regular. Please make contact with Esri UK Technical Support if you expertise any additional problems