When executing a process which connects to an FTPS server, the following error is raised:

    com.indy.engine.common.exceptions.EngineExceptionI: 550 SSL/TLS required on the data channel
    at com.indy.engine.actionCodes.FtpPutActionCodeI.executeSimpleCode(SourceFile:394)
    at com.indy.engine.action.common.ActionCodeTypeI.executeCode(SourceFile:1608)
    at Source)



This error message is raised by the FTPS server, because it expects encryption of the data channel.

See RFC2228 for more information.

The solution is to enable the FTP_ENCRYPT_CHANNEL_DATA parameter on the FTP action.