Data Merge won't add file

I use data merge regularly for wedding stationery. I have never had issues with it and nothing was done differently this time around. 

My CSV file does not have spaces in its column titles, there is no formatting included and the file is closed prior to trying to add it to my indesign file. 

It will let me select the file and click open, but it is not generating in my data merge dialog box.

I have restarted the program, checked for an update, restarted my computer and tried multiple InDesign files as well as CSV files to ensure it wasn't just the project I'm currently working on but none of it has helped.

Please help!