PGN file cannot be opened when sent using WhatsApp

I play chess quite every weekend. After the game, I enter my game moves into [Analyze This](https://play.google.com/store/apps/details?id=com.pereira.analysis) , and see my errors. Then, I save a [PGN](https://en.wikipedia.org/wiki/Portable_Game_Notation) file into my Android phone. Then, I have 2 ways to share it : 1) I send the PGN file "attached" to an email, and *all* my colleagues that receive it can re-play it on their "Analyze This" app, clicking on the attached file. 2) I send it using "WhatsApp" - no way they can play it (even me !) - "You may not have a proper app for viewing this content" is the error message. Analyze This is v5.4.8. Android is version 11. Any clue?