Troubleshooting CFFTP - working connection is now failing

I’m using 5.3.7.47 on Windows. I had a scheduled task that downloaded files using cfftp that has been running successfully for weeks. It suddenly stopped working this past week, though other tasks that also use cfftp are still working. There’s a good chance that a change on the server side is causing the problem but I have no way to troubleshoot. Is there a way to generate a log from ftp operations? Any other advice? I tried downgrading to 5.3.6 but it’s still broken.

Can you elaborate on “Stopped working”?

Yeah, I guess that was pretty vague.

com.jcraft.jsch.JSchException: Session.connect: java.net.SocketException: Connection reset 
lucee.runtime.exp.NativeException: com.jcraft.jsch.JSchException: Session.connect: java.net.SocketException: Connection reset
    at lucee.runtime.net.ftp.SFTPClientImpl.handleFail(SFTPClientImpl.java:379)
    at lucee.runtime.net.ftp.SFTPClientImpl.connect(SFTPClientImpl.java:114)
    at lucee.runtime.net.ftp.FTPWrap.connect(FTPWrap.java:117)
    at lucee.runtime.net.ftp.FTPWrap.<init>(FTPWrap.java:61)
    at lucee.runtime.net.ftp.FTPPoolImpl._get(FTPPoolImpl.java:83)
    at lucee.runtime.net.ftp.FTPPoolImpl.get(FTPPoolImpl.java:38)
    at lucee.runtime.tag.Ftp.getClient(Ftp.java:495)
    at lucee.runtime.tag.Ftp.actionGetFile(Ftp.java:428)
    at lucee.runtime.tag.Ftp.doEndTag(Ftp.java:184)
    at org.lucee.cfml.helperbase_cfc$cf.udfCall1(/org/lucee/cfml/HelperBase.cfc:129)
    at org.lucee.cfml.helperbase_cfc$cf.udfCall(/org/lucee/cfml/HelperBase.cfc)
    at lucee.runtime.type.UDFImpl.implementation(UDFImpl.java:106)
    at lucee.runtime.type.UDFImpl._call(UDFImpl.java:344)
    at lucee.runtime.type.UDFImpl.call(UDFImpl.java:217)
    at lucee.runtime.ComponentImpl._call(ComponentImpl.java:680)
...