Tools

FTP Voyager cannot connect via FTPS and generates an error in Serv-U

FTP Voyager only works on TLS 1.0

First published date

11/14/2018 8:02 PM

Last published date

7/16/2019 5:42 PM

Overview

A user is trying to connect to Serv-U via FTPS using the FTP Voyager and then getting the error below.

“Unable to establish SSL connection (CLIENT ERROR: Client may have rejected the SSL certificate.  Ensure the SSL certificate has been issued by a certificate authority.)”

It is most likely an issue of unsupported TLS ciphers or TLS version. FTP Voyager is a free FTP client which requires TLS 1.0 to run properly using FTPS.  This FTP client does not have much development since it is a free client only.

Product section

Serv-U Managed File Transfer & Serv-U FTP Server

Cause

  • Disabled TLS 1.0 in Serv-U
  • Unsupported TLS 1.0 ciphers

Resolution

Please make sure TLS 1.0 is enabled in Serv-U, and the enabled TLS ciphers are supported by FTP Voyager such as AES256-SHA. Another option is to use another FTP client like Filezilla or WinSCP, etc.

To check the TLS configuration.
  1. Open Serv-U Management console.
  2. Go to the Global, select Limits and Settings.
  3. Select Encryption tab.
  4. Check if TLS 1.0 is active.
  5. Click Configure Cipher Suites to list the ciphers.