It seems you are trying to access:
ftp://localhost:21
Port 21 is the default port used for FTP (File Transfer Protocol), a standard network protocol used for transferring files between a client and server on a computer network.
To access FTP services on port 21, ensure your FTP server (such as vsftpd, FileZilla Server, or others) is running and configured to use this port. You can transfer files between your local machine and the FTP server using FTP client software.
Once your FTP server on port 21 is running, you can access its services through FTP client applications using URLs like:
localhost
and port 21
.ftp localhost
.If you're setting up FTP server for the first time:
Here are some useful folders and ports on web servers
xampp, apache, tornado etc...