TLS Handshake Error 80090308

This error can occur when the component is configured to use implicit TLS/SSL, but the server expects explicit TLS/SSL. To fix this, set the SSL mode to explicit:

ftp.SSLStartMode = FTPSSLStartModes.sslExplicit; Setting the correct SSLStartMode and RemotePort usually resolves this handshake error.

Note: If you are connecting through a proxy server, this error may indicate that your proxy does not support TLS.

The above steps are usually sufficient to resolve the error. If they do not, please refer to this error's section in our article on Common Windows Security Errors