Not filling my PDF

I am trying to get this working in my dev site and am failing! I can't figure out what I could be doing wrong, but it just won't work.

I uninstalled everything, and reinstalled, then in an attempt to keep it simple, made a PDF with two fields (Name and Date). Fill PDF does identify the correct "Keys" (same as the field named in the PDF). I set the values on those fields to whatever I want (statically even), load the URL as /fillpdf?fid=xxxx (based on the (Form Info") and it presents me the PDF without filling it.

I have searched through issues, I have re-read all the documentation I can find and am coming up empty.

Thanks in advance for your help!