When an FTP connection fails, verify the connection details before changing server files.
- Confirm the protocol, hostname, port, username, and password.
- For a separate FTP account, use the complete username shown in cPanel.
- Check whether the FTP account has been restricted to a different home directory.
- Check the FTP quota and the cPanel account's overall disk quota.
- Verify that the destination directory exists and is writable by the account.
- If SFTP is being used, confirm that shell/SSH access is actually enabled.
Repeated authentication failures usually indicate a credentials/protocol problem, while successful login followed by failed uploads more often points to quota, directory, or permission issues.
