'Bad Request 400' response when getting outlook ics url

I've been running into issues on a legacy project that fetches ical feeds.

I am getting a response of "Bad request 400" when trying to get a calendar via any outlook.office365 url.

I have tested all the urls using PostMan and an online ics validator so I know that it has nothing to do with the calendars themselves not being available.

I am using the npm package 'request' to get the calendars and it's working with any url that doesn't come from the outlook.office365.com host.

For privacy reasons i'm not able to share any of the urls used.

Here is where the request is sent.

async.waterfall([
        cb => {
          request.get(url, {}, function (err, r, data) {
            console.log('response', r.statusCode); // this will be 400 for any outlook.office365 ics url but not for others.
            if (err) return cb(err, null);
            try {
              ...
            } catch (err) {
              ...
            }

Are there any headers that need to be attached in order to receive outlook.office365 calendars? I can't find anything online about what is required