If you receive this error when trying to connect to your account via FTP:
421 Home directory not available - aborting
this means that the FTP user you are trying to log in with is configured to use a home directory which does not exist.
The problem can easily be fixed by creating the directory set as home for the FTP user. You can see which directory each FTP user has from your cPanel > FTP Accounts. The directory will be shown in the Path section of the page.