1633267 - FTP: 421 Unexpected reply codeTerminating connection

When retrieving files from FTP server using the File FTP Adapter, the following error appears in the logs:

Disconnect from ftp server dummy.ftp.server

Sending command 'QUIT'
ftp server returns reply '221 '
Sending command 'NOOP'
with 421 Timeout (120 seconds): closing control connection.
ftp server returns reply '421 Timeout (120 seconds): closing control connection.'

[EXCEPTION]
com.sap.aii.adapter.file.ftp.FTPEx: 421 Unexpected reply codeTimeout (120 seconds): closing control connection.
at com.sap.aii.adapter.file.ftp.FTPCtrl.validateReply(FTPCtrl.java:557)
at com.sap.aii.adapter.file.ftp.FTPCl.nop(FTPCl.java:1833)
at com.sap.aii.adapter.file.File2XI.checkResourceIntegrity(File2XI.java:5749)
at com.sap.aii.adapter.file.File2XI.invoke(File2XI.java:708)
at com.sap.aii.af.lib.scheduler.JobBroker$Worker.run(JobBroker.java:529)
at com.sap.engine.core.thread.impl3.ActionObject.run(ActionObject.java:37)
at java.security.AccessController.doPrivileged(Native Method)
at com.sap.engine.core.thread.impl3.SingleThread.execute(SingleThread.java:185)
at com.sap.engine.core.thread.impl3.SingleThread.run(SingleThread.java:302)

• SAP NetWeaver
• SAP Process Integration

IETF, 959, PO, NetWeaver, XI, AEX, File adapter, FTP server, Process Integration 7.11, PI 7.11, Process Integration 7.30, PI 7.30, Process Integration 7.31, PI 7.31, Process Orchestration 7.4, PI 7.4, PO 7.4, Process Orchestration 7.5, PI 7.5, PO 7.5, XI, AEX , KBA , BC-XI-CON-FIL , File Adapter , Problem