Drupal 7 - Sharepoint rest integration

We are using drupal version 7 as the base

We installed Sharepoint REST module version 7.x-1.0-alpha3

We created account on our sharepoint 2013 instance to help contact with drupal site

While configuring the module we are encountering following message

On Module -> Sharepoint Rest setting -> Debug Info

Error:

SharePoint Rest error: The specified member name is either invalid or empty

Could not connect to SharePoint. Check module settings

Could anyone share example or issues related to this

Currently URL for site is like

https://domainname.com
username : domain\username
Should it be some thing else