If you can share a small snippet of the raw source (HTML or the email MIME structure), I can point to the exact lines to change.
Here is what each typically represents:
Given the combination of these terms, if you're asking about how to identify or work with a CID font that has been designated or referenced as "f1 f2 f3 f4", here are some informative points: cid font f1 f2 f3 f4
in an error message, you aren't looking at the font's real name. Instead, these are internal labels assigned by a PDF generator: CID+ Fonts - Adobe Community If you can share a small snippet of
When a PDF is generated, the software compiles a list of fonts used in the document. To save space and simplify internal references, it assigns a short alias: To save space and simplify internal references, it