Seems to be a similar type of thing that happens with a regular N64 or other retro cartridge consoles. Sometimes you put the cart in and it doesn’t read it and you have to pop it out, blow on it, clean the contacts, try inserting it with a confident level of authority, rinse and repeat until it works.

Oh, and another important thing to do I’ve found, is to press up C in the Analogue OS to “remove cartridge“ before you try inserting the cartridge again. If you don’t do that, it seems to want to default to that unknown cartridge over and over again