OK I have enabled 'Maildir' within => Management => Server => Settings => Email.
Using ThunderBird I can press 'Retrieve Email' and password acceptance is OK...
The server says there is no email, even though I sent one to this address from a Yahoo account as a test.
Also, if I attempt to send an email outwards from the server I am perpetually prompted for the email account password which never ever succeeds!
What should I check to enable proper function to the email server?
Thanks for your help