[qmailtoaster] The mail server responded this user has no $HOME/Maildir

[Tony White]

Hi folks,  I have no idea what this is but noone can get email.Trying to 
retrieve mail generates the error...
Sending of password for u...@example.com did not succeed.Mail server ServerName 
responded: this user has no $HOME/Maildir
Anyone any ideas please? I will keep searching the net meanwhile.
TIA.
tony