Error 8016 means the variation data in your file is incomplete. A variation family has one parent row and a set of child rows. The parent row states the variation theme, the attribute the children differ by, such as color or size. Each child row has to name its parent, carry the same theme, and carry its own value for the theme attribute. A row where one of those pieces is missing or disagrees with the rest of the family returns error 8016.
The processing report gives five entries for each failed row: the record number, the SKU, the error code, the type, and a message. Record 1 is row 3 of your file, so the row for a record sits at the record number plus two. For error 8016, the message names the SKU of the failed row. It does not name the column that is wrong. The report therefore tells you which row failed, and the check of the family around that row is left to you. The error is reported per row, so a family with several incomplete children returns several 8016 errors.
A family is held together by values repeated across its rows. The variation theme column states the theme on the parent row and repeats it on every child row. The parentage column marks which row is the parent and which rows are children. Each child row names the parent SKU in the parent SKU column, and the theme attribute columns, such as color and size, carry each child's own value. Amazon reads the family as a set. A child row with an empty theme cell, an empty parent SKU cell, or an empty color cell while its siblings carry a color does not join the set, and that row returns 8016.
A submission can carry errors that sit outside the file. A missing brand registration or approval returns error 5665. A missing permission to list in the category returns error 8026. Editing the file does not repair either one. The diagnosis lists those errors separately, with the reason and the step to take in Seller Central, and we do not call them fixed.
The free diagnosis reads your failed file and the processing report Amazon returned. It shows every error by SKU, states which errors we fix automatically, which ones need your answer, and which ones the file cannot fix. You see the full breakdown before you pay anything. You can start from the FixFlatFile home page.
Requirements differ by category, and Amazon decides whether a file is accepted.