Indesign Margins Set Correctly But Amazon KDP Does not Accept Them

I have a very frustrating challenge. I have finished writing, editing, and laying out my first novel in indesign--interiors and cover design 243 pages in all, but after I upload my paperback manuscript to Amazon KDP, then press print previewer, there is an error-- "Insufficient gutter. Books with with 243 pages require at least 0.5" for the gutter (inside margin) and at least .25" for the outside, top and bottom margins."

But the thing is, I set up through indesign:

Top margin .75 in

Bottom margin .5 in

Inside margin .75 in

Outside margin .5 in

Now, KDP seems to say there are only 2 places --one on page 53 an one on on page139-- where the is a margin error. They are both areas where I used some italics.  Hmm.

Please help.

This won't be the first time I have been rescued by this community! 

Thank you,  

Kevin