I have received a PDF from a magazine contributor, for insertion in the magazine I'm designing.
However, when I place the PDF I get a warning that the version is incompatible with the PDF export version.
There is a button to "fix" this issue. However, after pressing it, the PDF warning disappears and a number of new errors appear about missing fonts. Those in turn have "Fix" buttons, which open the font manager, but the "missing" fonts aren't listed in Font Manager.
The PDF appears fine when printed out, so I'm not sure why Publisher thinks there is an issue. What is the best way of fixing these problems, as it's really annoying (and a potential source of errors) having a popup telling me that there are Preflight warnings every time I go to export.