onContentUploadError_ handler for Request header field X-Upload-Content-Type is not allowed by Access-Control-Allow-Headers in preflight response.

[bcaballero]

I'm having an intermittent error on the uploader when trying upload videos. There are times that I got this error on console.

PUT https://1512364271.cloud.vimeo.com/upload?ticket_id=cedf9e8b71b28c5e1825b2d…66&video_file_id=803367585&signature=92253552173556f613ef26f17c9df4bb&v6=1 net::ERR_CONNECTION_RESET first.js:22460 XHR failed loading: PUT "https://1512364271.cloud.vimeo.com/upload?ticket_id=cedf9e8b71b28c5e1825b2d…66&video_file_id=803367585&signature=92253552173556f613ef26f17c9df4bb&v6=1".

me.sendFile_ @ first.js:22460 (anonymous) @ first.js:22416

This results to numerous request on vimeo, ending up with 429 error on Vimeo related to rate limits.

XMLHttpRequest cannot load https://1512364271.cloud.vimeo.com/upload?ticket_id=cedf9e8b71b28c5e1825b2d…66&video_file_id=803367585&signature=92253552173556f613ef26f17c9df4bb&v6=1. Request header field X-Upload-Content-Type is not allowed by Access-Control-Allow-Headers in preflight response. first.js:22478 XHR failed loading: PUT "https://1512364271.cloud.vimeo.com/upload?ticket_id=cedf9e8b71b28c5e1825b2d…66&video_file_id=803367585&signature=92253552173556f613ef26f17c9df4bb&v6=1". me.resume @ first.js:22478 me.onContentUploadError @ first.js:22610

After series of debugs, I found that the error was triggered within the onContentUploadError handler. It falls within the retryHandler which causes an infinite loop.

`/**

• Handles errors for uploads. Either retries or aborts depending
• on the error.
• @private
• @param {object} e XHR event */ me.prototype.onContentUploadError = function(e) { if (e.target.status && e.target.status < 500) { this.onError(e.target.response) } else { this.retryHandler.retry(this.resume()) } }`

Any suggestions on how to fix this issue? Thank you in advance.