If this doesn't work, then please reattach with an unprotected version of that sheet.

Try this in cell C17:

=IFERROR(INDEX('Loan Data'!$B$18:$K$11017,MATCH

It is because you are subtracting 1 from the date in the original formula, and then it can't match. I put in a formula that says, if there's no match, then try it without subtracting 1 from the date and give me that information instead.