Symptom
When executing aprocess which connects to an FTPS server, the following error occurs on the FTP action:
javax.net.ssl.SSLException: 503 You must issue the PBSZ command prior to PROT
at org.apache.commons.net.ftp.FTPSClient.execPROT(FTPSClient.java:426)
at com.indy.engine.actionCodes.d.b.connect(SourceFile:285)
at com.indy.engine.actionCodes.FtpPutActionCodeI.executeSimpleCode(SourceFile:277)
at com.indy.engine.action.common.ActionCodeTypeI.executeCode(SourceFile:1608)
at com.indy.engine.action.common.ActionCodeTypeI.run(SourceFile:1767)
at java.lang.Thread.run(Unknown Source)
Solution
This error message is raised by the FTPS server.
See RFC2228 for more information on the PROTECTION BUFFER SIZE (PBSZ) command:
This command allows the FTP client and server to negotiate a
maximum protected buffer size for the connection. There is no
default size; the client must issue a PBSZ command before it can
issue the first PROT command.
The solution is to enable this parameter on the FTP action:
Please contact the FTPS server's admin to define the value.