Cannot Group Data in Excel 365

Hello, 

I cannot get a pivot table to group data.  Any data.  Specifically, I'm trying to group dates by month.  I have verified that there are no empty cells.  I have also verified that the dates are formatted as dates. 

My account is through Office 365.  However, I am not trying to work in the web browser. I am using the desktop version.  

I've tried browsing through previous discussions and have ruled out the above.  What am I missing?  The whole point of pivot tables is to be able to summarize data, but I'm having a hard time actually summarizing the data.  All of the tutorials show options which I don't seem to have. 

I feel like I'm missing something very obvious.  Can anyone offer any other insights?