Schedule on organiser interface loading eternally

[mariobehling]

The schedule on organiser interface loading eternally. There is a JSON error showing in the console

compare: https://app.eventyay.com/talk/orga/event/wikiindaba/submissions/HCTBBA/

Failed to load resource: the server responded with a status of 404 ()
main-1647aa4a.js:1 SyntaxError: Unexpected token '<', "


<!DOCTYPE "... is not valid JSON