Cause

You created specific project structure and defined identifierblocks to which you assigned structure identifiers. Now there are conflicting structure identifiers for the placed part and for the corresponding mounting surface, in one of the identifier blocks.

Solution

1. Enter the same structure identifiers for the relevant identifier blocks (e.g. for "Higher-level function" and / or "Mounting location") for the placed part and the corresponding mounting surface (in the Properties <...> dialog under Displayed DT).
2. Then start a new check run.