Login problems were caused by the fact that the syntax required by the external users module, used to allow login with Eskimo system logins, changed between 14.10 and 15.07 but nothing bothered to check this or tell me about it.  The config.php syntax has been corrected to work with the newer version.

     You will need to agree to terms of service, if you do not, service will not be provided.  If you are using automated apps, before they will work you will need to login to the website:

     https://www.eskimo.com/nextcloud/

     And tick the ‘Accept Terms of Service’ box.