This singleton run-time message occurs when generating a diary if an instruction is encountered to set the font of a given token replacement to a vertically oriented font whose name begins with the at character (@).
Fonts whose names begin with the at character (@) are the legacy vertically oriented fonts of early versions of Windows 32-bits, and these screen-only fonts should not be used for print with QuarkXPress or InDesign.
You should always use the version of the font whose name does not begin with the @ character.
See also: why do some font names begin with an at-sign?, vertical writing and printing.
Topic 187375, last updated on 17-Apr-2023