I installed my october cms in a subfolder www.url.com/octobercms the events however are tried to get from www.url.com instead of the sub directory:
http://localhost/api/christophheich/calendar/feed/null?start=2019-07-28&end=2019-09-08&_=1565621815162 should be: http://localhost/octobercms/api/christophheich/calendar/feed/null?start=2019-07-28&end=2019-09-08&_=1565621815162