Excel function not working

OUTLOOK670 

In addition to all above, if write such formulas when use at least some formatting

=IF(ItemName="",
   "",
   CONCATENATE(
      IF(OR(
            VendorMapRules="update",
            AND(PurchasePrice=0,MAP=0),
            AND(
               IFERROR(ShipCost=0,FALSE),
               ShipCostOverride="no override",
               MAP=0
            ),
            ISERROR(ShipCost),
            AND(
               Disc="yes",
               MapRequired="yes",
               VendorMapRules<>"NO MAP"
            ),
            ISERROR(FloorPriceAdjusted*1),
            AND(
               IFERROR(ProfitAtFloor+0.01<DesiredProfit,FALSE),
               ExcludedFloor="",
               FollowExcluded="Follow excluded",
               VendorMapRules<>"Set at base"
            ),
            VendorMapRules="",
            AND(
               DSItem=TRUE,
               DSFee=0,
               ifna(ItemFulfillmentCost=0,TRUE)
            )
         ),
         "Error:",0),
      IF(
         VendorMapRules="update",
         " Update vendor MAP rules",""
      ),
      IF(
         AND(PurchasePrice=0,MAP=0),
         " $0 purchase price",""
      ),
      IF(
         AND(IFERROR(ShipCost=0,FALSE),
            ShipCostOverride="no override",MAP=0
         ),
         " $0 ship cost",""
      ),
      IF(
         ISERROR(ShipCost),
         IF(
            SalesChannel="FBM",
            " Missing shipping data",
            "No FBA fulfillment fee"
         ),
         ""
      ),
      IF(
         AND(
            DSItem=TRUE,
            DSFee=0,
            ifna(ItemFulfillmentCost=0,TRUE)
         ),
         " No DS fee",
         ""
      ),
      IF(
         VendorMapRules="",
         " No vendor MAP rule",
         ""
      ),
      IF(
         AND(
            IFERROR(ProfitAtFloor+0.01<DesiredProfit,FALSE),
            ExcludedFloor="",
            FollowExcluded="Follow excluded",
            VendorMapRules<>"Set at base"
         ),
         " Profit lower than desired",
         ""
      ),
      IF(
         ISERROR(FloorPriceAdjusted*1),
         " Floor cannot be calculated",
         ""
      ),
      IF(
         AND(
            Disc="yes",
            MapRequired="yes",
            VendorMapRules<>"NO MAP"
         ),
         " MAP & disc",
         ""
      )
   )
)

OUTLOOK670 

I would suggest you break out the 10 IF statements inside the CONCATENATE function into 10 separate cells, and then reference the 10 separate cells in the CONCATENATE

OUTLOOK670 

Riny is being kind when he describes that as "an incredible function"

In fact it's a casebook example of a DYSfunctional Function. I think any good reference manual on Excel will warn that just because it's possible to write a formula that is, whatever, a 1,000 characters long, doesn't mean it's a good idea. It might be fun to have written such a function and to have had it work on occasion. I've written function formulas that are nested three or four levels deep, but what the reference manuals will tell you is that they're hard to decode or understand even when they do work, and for all practical purposes impossible to maintain.

So yes, break it apart--in your case, probably into ten or twenty separate cells with ten or twenty separate results, some of them "TRUE" or "FALSE," with some kind of notation as to what each is telling you... 

OUTLOOK670 

What an incredible function. Would say it's almost impossible to maintain. It refers to a lot of named ranges. If one or more are missing in your workbook, you'll get the #NAME error. Consider a  combination of simpler functions to achieve whatever you are after.