Sometimes we get a error Message when using the FTP clients: 421 Sorry, cleartext sessions are not accepted on this server.
Problem: This error mean that the FTP provider has secured the access with Transport Layer Security (TLS) or its predecessor, Secure Sockets Layer (SSL).
Change the protocol of the host to “ftpes://”
The configuration will be
a) Login to WHM b) Go To : Service Configuration c) Click on : FTP Server Configuration and set TLS Encryption Support : to “Optional