Problem

-- New external FTPS implicit server connection fails

-- Logs show the command channel is established successfully, user logged in and issued commands successfully that require a data channel

-- Logs show the error: "javax.net.ssl.SSLException: Unrecognized SSL message, plaintext connection?" for the data channel connection

Resolution

** Interchange will only communicate with an external FTPS server via an encrypted command and an encrypted data channel. Some FTPS servers have the implicit data channel encryption turned off by default. To solve the issue, the server must be instructed to encrypt the data channel as well.

To solve the issue, follow this procedure:

1. In the UI, go to the exchange point in question
2. Switch to the "Advanced"-tab
3. In the "User commands" field enter these two lines:
   @PBSZ 0
   @PROT P
4. Save the exchange point