Updated: 8 October 2026 · Applies to: FileZilla Client 3 (menu labels and defaults checked in the FileZilla 3.71.0 source); limit behaviour tested with Pure-FTPd 1.0.50 on Debian 13; Centova Cast FTP (cc-ftpd)
421 Too many connections (2) from this IP means the FTP server accepts at most 2 connections at the same time from your IP address, and FileZilla tried to open one more. The number in brackets is the server's limit, not a count of your connections (an earlier version of this article wrongly said Centova Cast allows only one). The fix is on your side: in FileZilla open File > Site Manager, select the site, and on the Transfer Settings tab tick Limit number of simultaneous connections with Maximum number of connections set to 2 (or 1). Server owners who want a higher limit on a Centova Cast server should see increasing the maximum FTP connections per IP.
How to read the message
According to Centova, its FTP server is a modified Pure-FTPd. We set a standard Pure-FTPd to allow 2 connections per IP address and opened three logins from one computer:
connection 1: 230 OK. Current restricted directory is / connection 2: 230 OK. Current restricted directory is / connection 3: 421 Too many connections (2) from this IP
- The refusal came straight after connecting, before the password was sent, so your login details are not the problem.
- The number is whatever the server is set to;
(2)means a limit of 2. - A different wording, such as
421 3 users (the maximum) are already logged in, sorry, is the server's total limit for everyone, not a per-IP limit; FileZilla settings will not fix that one, so try again later. Other FTP servers word the message differently: see FTP error 421 on Pure-FTPd, ProFTPD and vsftpd.
Why FileZilla goes over the limit
- Default settings. FileZilla keeps one connection for browsing folders, and each transfer opens its own. Maximum simultaneous transfers is 2 by default, so an upload of several files can use three connections.
- Several tabs. Every tab connected to the same server (File > New tab) holds its own connection.
- A shared IP address. Other computers or FTP programs behind the same office or home router count against the same limit.
- Sessions that did not close. After a crash, sleep or network change, the server keeps counting the old session until its idle timeout ends it (15 minutes by default on Pure-FTPd).
Fix 1: limit connections for this site
- Open File > Site Manager... (Ctrl+S) and select your site. To create one, see configuring your website in FileZilla.
- Open the Transfer Settings tab.
- Tick Limit number of simultaneous connections and set Maximum number of connections to the number in the error message, or to 1.
- Click Connect.
FileZilla's source shows that this limit includes the browsing connection, and that with a limit of 1 FileZilla sends transfers over the browsing connection. The setting only applies when you connect from Site Manager; if you use the Quickconnect bar, use Fix 2.
Fix 2: fewer transfers for every server
- Open Edit > Settings... and select Transfers.
- Under Concurrent transfers, set Maximum simultaneous transfers to 1 (allowed range 1 to 10).
- Click OK.
Browsing plus one transfer then needs two connections. The Limit for concurrent downloads and Limit for concurrent uploads fields (0 means no limit) only divide that number between directions; they do not raise it.
Fix 3: clear old sessions
- Use Server > Disconnect (Ctrl+D) in every tab and close the tabs you do not need. Close other FTP programs too.
- Wait for the server to drop stale sessions, then use Server > Reconnect (Ctrl+R). FileZilla's own connection settings warn that some servers ban clients who reconnect too often.
- If Send FTP keep-alive commands is ticked (Edit > Settings... > Connection > FTP), idle FileZilla windows keep their connections open. FileZilla notes that a proper server does not need it.
Still stuck?
- FileZilla's message log shows the server's exact reply; see checking your FTP client's log.
- Cannot connect at all: unable to connect with FTP to upload music. Uploads fail after login: errors uploading to Centova Cast by FTP.
- On Ucartz Shoutcast and Icecast hosting the limit is a server setting: if it is too low for your uploads, open a support ticket.
Official documentation: Pure-FTPd manual (per-IP limit -C, idle time -I).
