The problem with sending large video to Facebook by Facobook.Client

[kiczmaker]

There is a problem with putting a video > 20MB from my own applications on Facebook wall. Videos < 20 MB place without problems, however, more give the following error:
Facebook.WebExceptionWrapper: An error occurred performing a http web request. ---> System.Threading.Tasks.TaskCanceledException: A task was canceled.
at System.Net.HttpWebRequest.EndGetResponse(IAsyncResult asyncResult)
at Facebook.HttpWebRequestWrapper.EndGetResponse(IAsyncResult asyncResult)
at Facebook.HttpHelper.ResponseCallback(IAsyncResult asyncResult, Object userToken)
--- End of inner exception stack trace ---

This problem occurs in Windows 10 UWP.
What could be the reason? Are they any restrictions or Facebook or Facebook.client?