You are trying to list an item and get the error message from Amazon: There is a restriction in effect at the item level (because of Item-Level gatings on an offer).
You are listing against an existing ASIN, however Amazon have restricted marketplace sellers from selling against this ASIN with particular product conditions. For example Amazon is only permitting listing against the ASIN for used items and the item you are selling is a new item.
1. Use the Find barcode wizard to match against a different ASIN (a different existing Amazon listing).
2. Ensure the condition of your product is specified correctly.