A problem with ftp connection

[Kennyyan66]

Hi ya, there's a problem with the ftp connection.
I set up an ftp server and used intranet penetration to enable me to access it from other places.
I can use windows explorer to connect to another computer which connected to a different network. When using the plugin, it prompts "No further information"
I might be a little unfamiliar with this, could you please guide me, thanks.

Environment: minecraft 1.19.4 paper, ebackup 1.3.1

> ebackup testupload
[21:44:59 INFO]: Starting upload test...
[21:44:59 INFO]: [eBackup] Starting upload of plugins\eBackup\uploadtest.txt to FTP server...
[21:45:01 WARN]: java.net.ConnectException: Connection refused: no further information
[21:45:01 WARN]:        at java.base/sun.nio.ch.Net.pollConnect(Native Method)
[21:45:01 WARN]:        at java.base/sun.nio.ch.Net.pollConnectNow(Net.java:672)
[21:45:01 WARN]:        at java.base/sun.nio.ch.NioSocketImpl.timedFinishConnect(NioSocketImpl.java:549)
[21:45:01 WARN]:        at java.base/sun.nio.ch.NioSocketImpl.connect(NioSocketImpl.java:597)
[21:45:01 WARN]:        at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:327)
[21:45:01 WARN]:        at java.base/java.net.Socket.connect(Socket.java:633)
[21:45:01 WARN]:        at ebackup-1.3.1.jar//org.apache.commons.net.ftp.FTPClient._openDataConnection_(FTPClient.java:920)
[21:45:01 WARN]:        at ebackup-1.3.1.jar//org.apache.commons.net.ftp.FTPClient._storeFile(FTPClient.java:653)
[21:45:01 WARN]:        at ebackup-1.3.1.jar//org.apache.commons.net.ftp.FTPClient.__storeFile(FTPClient.java:639)
[21:45:01 WARN]:        at ebackup-1.3.1.jar//org.apache.commons.net.ftp.FTPClient.storeFile(FTPClient.java:2030)
[21:45:01 WARN]:        at ebackup-1.3.1.jar//dev.espi.ebackup.BackupUtil.uploadFTP(BackupUtil.java:277)
[21:45:01 WARN]:        at ebackup-1.3.1.jar//dev.espi.ebackup.BackupUtil.lambda$uploadTask$1(BackupUtil.java:201)
[21:45:01 WARN]:        at org.bukkit.craftbukkit.v1_19_R3.scheduler.CraftTask.run(CraftTask.java:101)
[21:45:01 WARN]:        at org.bukkit.craftbukkit.v1_19_R3.scheduler.CraftAsyncTask.run(CraftAsyncTask.java:57)
[21:45:01 WARN]:        at com.destroystokyo.paper.ServerSchedulerReportingWrapper.run(ServerSchedulerReportingWrapper.java:22)
[21:45:01 WARN]:        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
[21:45:01 WARN]:        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
[21:45:01 WARN]:        at java.base/java.lang.Thread.run(Thread.java:833)
[21:45:01 INFO]: [eBackup] Upload of plugins\eBackup\uploadtest.txt has failed.