I tried each and everything without success. On my PC Gotham Book Italic is shown as missing in APub's resources dialog although it's properly displayed in the document. All other Gotham fonts work fine and on another Windows PC everything works fine with the same Gotham font set.
As Gotham Book Italic displays and prints fine despite of the error message i'll stop wasting time with the strange Windows font system. Thank you very much for all your assistance and best regards to LibreTraining for the care package.
polyeder got a reaction from Sean P in issue with OTF italic fonts