Make sure you do not have "emulate cloud security" enabled under -> project -> settings -> configuration -> "default" (or your own) -> server -> emulate cloud security.
What Jaap suggested or add
permission java.net.SocketPermission "127.0.0.1", "resolve";
to the .policy file in the folder location of your business modeler (i.e. C:\Program Files (x86)\Mendix\4.5.2\runtime)
Update This new exception you are experiencing originates from the library(JSch) this Mendix module uses. To be pointed to the cause of this exception, you could google for it as the problem seems to be in your current server set-up. After some further investigation: According to the filezilla project, filezilla server does not support SSH.
Chech this thread which discusses SFTP Servers to enable you to test locally.
Thanks Jaap and Roeland. I did what you both said but now the 'Access denied' error has changed to this 'Auth fail' error. However, I am confidant that I have entered valid credentials. Do you have any suggestions?
An error has occurred while handling the request. [User 'admin' with session id '256662b4-a153-47ed-b5c6-97ca952053e0' and roles 'Administrator']
--------
lg: com.mendix.core.CoreRuntimeException: com.mendix.systemwideinterfaces.MendixRuntimeException: JschException occured for document with action LIST.
at SFTPConnection.GetFileList (JavaAction : 'Call 'GetFileListFromSFTPLocation'')
Advanced stacktrace:
at mx.a(SourceFile:185)
Caused by: com.mendix.core.CoreException: com.mendix.core.CoreRuntimeException: com.mendix.systemwideinterfaces.MendixRuntimeException: JschException occured for document with action LIST.
at com.mendix.core.Core.execute(SourceFile:232)
Caused by: com.mendix.core.CoreRuntimeException: com.mendix.systemwideinterfaces.MendixRuntimeException: JschException occured for document with action LIST.
at hE.b(SourceFile:218)
Caused by: com.mendix.systemwideinterfaces.MendixRuntimeException: JschException occured for document with action LIST.
at sftpconnection.helpers.HandleFileSftp.handleFile(HandleFileSftp.java:143)
Caused by: com.jcraft.jsch.JSchException: Auth fail
at com.jcraft.jsch.Session.connect(Session.java:484)
at com.jcraft.jsch.Session.connect(Session.java:162)
at sftpconnection.helpers.HandleFileSftp.handleFile(HandleFileSftp.java:95)
at sftpconnection.actions.GetFileListFromSFTPLocation.executeAction(GetFileListFromSFTPLocation.java:45)
at sftpconnection.actions.GetFileListFromSFTPLocation.executeAction(GetFileListFromSFTPLocation.java:25)
at com.mendix.systemwideinterfaces.core.UserAction.execute(SourceFile:57)
at com.mendix.core.actionmanagement.CoreAction.call(SourceFile:457)
at hE.b(SourceFile:207)
at com.mendix.core.Core.execute(SourceFile:226)
at ln.a(SourceFile:69)
at mx.a(SourceFile:72)
at mw.a(SourceFile:151)
at mw.executeAction(SourceFile:98)
at com.mendix.systemwideinterfaces.core.UserAction.execute(SourceFile:57)
at com.mendix.core.actionmanagement.CoreAction.call(SourceFile:457)
at hE.b(SourceFile:207)
at com.mendix.core.Core.execute(SourceFile:226)
at gp.execute(SourceFile:186)
at jd.a(SourceFile:319)
at com.mendix.externalinterface.connector.RequestDispatching$Worker.a(SourceFile:170)
at com.mendix.externalinterface.connector.RequestDispatching$Worker$a.a(SourceFile:161)
at com.mendix.externalinterface.connector.RequestDispatching$Worker$a.apply(SourceFile:160)
at akka.actor.Actor$class.apply(Actor.scala:545)
at com.mendix.externalinterface.connector.RequestDispatching$Worker.apply(SourceFile:156)
at akka.actor.LocalActorRef.invoke(ActorRef.scala:910)
at akka.dispatch.MessageInvocation.invoke(MessageHandling.scala:25)
at akka.dispatch.ExecutableMailbox$class.processMailbox(ExecutorBasedEventDrivenDispatcher.scala:223)
at akka.dispatch.ExecutorBasedEventDrivenDispatcher$$anon$4.processMailbox(ExecutorBasedEventDrivenDispatcher.scala:123)
at akka.dispatch.ExecutableMailbox$class.run(ExecutorBasedEventDrivenDispatcher.scala:195)
at akka.dispatch.ExecutorBasedEventDrivenDispatcher$$anon$4.run(ExecutorBasedEventDrivenDispatcher.scala:123)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
at java.lang.Thread.run(Thread.java:662)
at akka.dispatch.MonitorableThread.run(ThreadPoolBuilder.scala:192)