XMLHttpRequest returning request.status 0 for only certain URL on site

Question

I have a React Native app that is downloading and parsing ical/ics files from public feeds to get sports team schedules. When I use the url for a single team's schedule everything works great and 200 is returned.

var request = new XMLHttpRequest();
    request.open(
      "GET",
      "http://athletics.cgps.org/calendar/team_112.ics",
      true
    );
    request.send(null);
    request.onreadystatechange = () => {
      console.log(request.status);
    }
  };

When I try a url that downloads the schedule for all teams from the same website / FQDN it fails. This url is much longer and pulls down much more data. I don't think it could be a CORS issue since another feed from the same site works. Both URLs work fine if entered directly into a web browser. But this one returns 0:

var request = new XMLHttpRequest();
    request.open(
      "GET",
      "http://athletics.cgps.org/cf_calendar/feed.cfm?type=ical&teams=0,155,118,117,116,115,146,145,142,143,144,133,139,138,148,114,113,111,112,140,131,147,134,141,120,119,127,126,124,125,130,129,128,123,137,135",
      true
    );
    request.send(null);
    request.onreadystatechange = () => {
      console.log(request.status);
    }
  };