Check your Options > Files > Support File Search Path . Ensure the folder where you saved the font is listed at the top of the search priority.
Whether you are trying to fix a broken drawing or upgrading your workstation, here is everything you need to know about downloading and installing the UPD (updated) version of this essential CAD resource. What is ADS CivilSHX? download font ads civilshx upd
Makes the drawing readable for collaborators using different Civil 3D versions. Check your Options > Files > Support File Search Path