This post explains why File Sender channel fails with the following error:
com.sap.aii.adapter.file.ftp.FTPEx: 550 *** ERROR *** NO BATCHES FOR TRANSMISSION
In the file sender, you indicate the directory from which the file must be picked. Let us say /SourceDirectory. Let us assume that the communication channel is configured to pick the file filename.ext. Now when a channel polls, it tries to pull ftp://senderftp.com/SourceDirectory/filename.ext. This access would fail if the FTP server is configured with /SourceDirectory as root location as the access would then be translated at the ftp server as ftp://senderftp.com/SourceDirectory/SourceDirectory/filename.ext.
You should either adjust the directory location or ask the FTP server support team to correct the FTP root; the latter is recommended.