Established Connection Aborted by Software in your host machine

I'm unable to connect with FTP, the log looks like this:
[15:54:18] Resolving host name ""
[15:54:18] Connecting to Port: 21
[15:54:18] Connected to
[15:54:18] 220---------- Welcome to Pure-FTPd [TLS] ----------
[15:54:18] 220-You are user number 5 of 50 allowed.
[15:54:18] 220-Local time is now 15:52. Server port: 21.
[15:54:18] 220-IPv6 connections are also welcome on this server.
[15:54:18] 220 You will be disconnected after 15 minutes of inactivity.
[15:54:18] USER anonymous@[deleted]
[15:54:18] 331 User anonymous@[deleted] OK. Password required
[15:54:18] PASS (hidden)
[15:54:18] An established connection was aborted by the software in your host machine.
[15:54:18] Server closed connection
[15:54:18] Cannot login waiting to retry (30s)...

I looked at the following article, which told me to change my connection from PORt to PASV, or vice-versa, and did so. It did not make a difference:

"An established connection was aborted by the software in your host machine. Software caused connection abort

This error can occur when the local network system aborts a connection, such as when WinSock closes an established connection after data retransmission fails (receiver never acknowledges data sent on a data stream socket), possibly due to a data transmission timeout or protocol error.

You may try to set the Connection Timeout higher (Default: 60s). If the problem persists change the Data Connection Mode in the Settings->Connection dialog from "Port Mode (PORT)" to "Passive Mode (PASV)" or vice versa."

Then I looked on the forum for similar articles, and there were many, but they all ended with either a referral to the above article, a referral to an article about firewalls interfering, or stating that the firewall was interfering. My only firewall is the windows XP one, and I tried disabling it, briefly, but it did not work. SFTP is also an exception for that firewall, for the record.

I'm at a dorm, so it's possible that the college is blocking port 21, I guess? If anyone knows any other possible causes or solutions, please let me know. Thank you.