TAG Historian Query not browsing Keys in the design panel

I am trying to use Tag Historian Query to populate time series graph. I created the Tag Historian Query just the same way as ignition university video shows. But when I go in the design panel (Reports) and under Data Source I can see the Tag HIstorian Query name however I am not able to select any keys as in the Tag Historian Query does not browse.

I have couple of screen shots but I don’t know how to upload it here.

Appreciate your help.