Scheduled refresh

Trying to set auto refresh for the dashboard created with DataSource using excel file located in the share point folder through Get data - Web option. While setting Data source credentials, authentication option as Oauth and privacy level as Organizational, i am getting below error:

"The OAuth authentication method isn't supported for this data source. Contact your admin."
Have tried changing the Authentication menthod, privacy level, none of them works.

Can someone help me here.