, you aren’t alone. You might have immediately searched for a "free download link" to fix it, but there’s a catch: CIDFont F1, F2, etc., are not actual font names that you can download from a font website.
If you know the person who created the PDF, this is the most permanent fix. Ask them to recreate the PDF with fonts embedded: cid font f1 f2 f3 f4 f5 f6 f7 fonts free download link
The following links point to officially redistributable versions of CID-keyed fonts or open-source equivalents. Always respect font licensing. For personal or educational use, these are safe. , you aren’t alone