As now the credentials problems are solved, I was trying to setup scheduled refresh, but the system says that the next refresh will be in year 9999.
Also can somebody please explain, how frequent is the default refresh for excel file source stored on SharePoint online? A lot of sources say hourly refresh, but I'm trying now only to implement the free subscription. Although I've started the 60 day pro trial, but the dasboards are shared with many people with free accounts.
Thanks for the help