Ftp error: 421 too many users

When I connect to a ftp server by typing ftp://servername

I got the following error messages:

421 too many users, please try it later.

What's the reason?

[Answer]

This is because there are too many users in the server currently.

Just wait for some time and try it again.

This is a server error rather than client error

However:

If you try to connect the server again and again with short interval, your IP may be forbidden for some time according to the virtual server's security policy.

So don't ftp to your virtual server too frequently or too many times.

You can use ftp in command line: open put close…