There are a few ways to connect by FTP to a host. The easiest way is using Internet Explorer which has the best ftp support.

In order to connect by FTP with your browser, you should just use the following address:

ftp://YourFtpUser:YourFtpUserPassword@yourdomain.com

However, if your FTP user to connect is similar to user@yourdomain.com then you will have to URL encode it like this:

ftp://YourFtpUser%40YourDomain.com:YourFtpUserPassword@yourdomain.com

In the above case it is important to note what the FTP username is:

YourFtpUser%40YourDomain.com

This address is URL-encoded and comes from YourFtpUser@YourDomain.com where @ has been substituted with %40, which is the ASCII code for @.

For more information about FTP you can check SiteGround's FTP Tutorial.

If you still have problems connecting by FTP, it is possible that your outgoing TCP port 21 is blocked by your local firewall or Internet service provider. If this is not the case, then your FTP server might be unreliable and you should transfer to a stable FTP service provider.