This error can also occur if you are using shared hosting because your hosting provider limits simultaneous FTP connections to prevent overloading the server.
Step 1. Repair from FileZilla
First, limit simultaneous connections in your FTP client configuration. That’s it:
- Start FileZilla and click File -> Site Manager.
- Under the Choose an entry section, select your site, and then click the Transfer Settings tab.
- Check the Limit Simultaneous Connections box and fill in the Maximum Connections field with your preferred number of connections. FTP maximum connections field
- Click OK to save the settings.
- Reconnect and see if the FTP error 421 goes away.
Tip: The number of connections may vary depending on your hosting provider. If you are not sure how many simultaneous connections are allowed, enter “8”. You can also contact your hosting customer support regarding this matter.
Step 2. Refresh (delete) inactive connections in cPanel (optional)
If you’re using cPanel, you can easily remove inactive FTP connections to fix too many 421 connections from this IP error:
- Go to your cPanel -> File -> FTP Connection.
- You will see all FTP connections in the Current Connections section. If you don’t see anything, press the reload button.
cPanel refresh (delete) inactive connections (optional)
- Under the Action column, click Disconnect next to the idle connection you want to close.
- Then, press the Disconnect button again to disconnect the FTP connection.
- Reconnect and check if the 421 error of FTP disappears.