I don't know why this "error" happens, but it does.

When you record words and start uploading them, you often have two or three recordings that fail due to the "badtoken" error. Since this error does not happen again when you click on the "upload failed recordings" button, we could easily avoid annoying the user.

What we should do is to automatically try re-uploading (once or maybe twice - to prevent infinite loops) a recording if, at the upload, the error was "badtoken".