Server Upload does not Always work?

I wanted to know why ALL my videos fail to send to the remote FTP server. When i have a small file about less than 40MB it will transfer to the remote server specified in the admin panel, but when I use a big file, over 100MB, then it converts correctly but does not even attempt to upload to my FTP server.

You need to check the debug log in templates_c folder while you upload large video, see if it get to the FTP part, if yes, there should be some time out during upload, this happen always or at times only ?

There seems to be some issue while creating folders on the remote FTP server.

Does the FTP server that you are connecting to have a file size limitation? Some FTP servers have a maximum file size that can be transferred over FTP.