Try 7z x Mandol.zip . 7-Zip is generally more robust with non-standard ZIP headers than the default Windows/macOS utilities.
Use Hexeditor or binwalk to find hidden offsets or fix the PK headers. Mandol.zip
If this is from a known security competition, it likely follows one of these patterns: Try 7z x Mandol
Run file Mandol.zip in a terminal. A standard ZIP should start with the hex signature 50 4B 03 04 . Mandol.zip