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Created 15 Mar 2003
Modified 29 Nov 2014

Article 165

500 Protocol not supported


500 Protocol not supported.


SmartFTP automatically sends an explicit command AUTH SSL and AUTH TLS to the FTP server to initiate a secure control connection. If the previous error occurs, it means that the server does not support SSL/TLS.


Please switch the Server Protocol from FTPS to FTP. For more information on how to do this please see the following Knowledge Base article:
KB: How To make a secure connection
If the problem still occurs after switching to Normal FTP, please contact your server administrator for further details.

For more information on explicit or implicit SSL please see the following Knowledge base article:
KB: What is the difference between implicit and explicit SSL