If you are looking for legitimate files and encountering "No Download" errors, here is how to fix your workflow:
A search for AdIllu2921M.zip reveals no legitimate software, no open-source project, no known publisher, and no documentation. In the cybersecurity field, random alphanumeric names like 2921M combined with "AdIllu" (possibly short for "Ad Illustration" or "Ad Illuminator") are often: If you are looking for legitimate files and
Use Windows Defender (built-in), Malwarebytes, or Kaspersky. Look for: no open-source project