That means that Oxide could not recognize that file as valid; this can generally happen when the encoding of the file was changed to something unsupported. If editing, make sure to save as UTF-8, and also try uploading as binary in your SFTP/FTP client if using one.

It was the first time, I downloaded the plugin and uploaded to server, I did not do any change.

I'd recommend trying it again as suggested, as the file does indeed load.