HiQPdf with special fonts

Question

I was trying to add this font to the PDF's that was generated by HiQPDF

@font-face {font-family: "Helvetica Neue LT Std";
src: url("//db.onlinewebfonts.com/t/f0db0faa0f4af4630e2db0cd30400f2c.eot");
src: url("//db.onlinewebfonts.com/t/f0db0faa0f4af4630e2db0cd30400f2c.eot?#iefix") format("embedded-opentype"),
url("//db.onlinewebfonts.com/t/f0db0faa0f4af4630e2db0cd30400f2c.woff2") format("woff2"),
url("//db.onlinewebfonts.com/t/f0db0faa0f4af4630e2db0cd30400f2c.woff") format("woff"),
url("//db.onlinewebfonts.com/t/f0db0faa0f4af4630e2db0cd30400f2c.ttf") format("truetype"),
url("//db.onlinewebfonts.com/t/f0db0faa0f4af4630e2db0cd30400f2c.svg#Helvetica Neue LT Std") format("svg"); }

Apparently it generates the PDF files without problem, but after i tried to open the PDF in Adobe Illustrator, AI catches a problem saying: "the document uses fonts that are currently unavailable on your computer" despite that i downloaded the fonts and installed in my pc.

I have used external urls because i am generating the pdfs from a server and not locally, so, i have those questions:

1. If I should upload the .ttf files to the server and from the server copy paste the links.
2. If the problem is with this font for being very particular
3. If I change the code for the font-face.

I need help to solve this problem, thanks for considering my request