Are you sure, both AE and AME are updated, you should update both to get them to work, what is the release number of both applications?
En ambas aplicaciones actualiza lo más que puedas en la versión 2021 que es la que estás utilizando.
Sorry for your issue.
The first thing I'd do is to check for the updates as suggested by the experts. If that doesn't help, what happens if you drag and drop the After Effects project in Media Encoder? Does it work that way?
Let us know.
My stuff is always up to date, it's been with these recent updates that completely bungles that ability to import anything into ME. No, I cannot drag and drop. And even if I could - THAT shouldn't have to be a workaround. You should be publishing and charging people for *functional* software. Even with this newest update in Jan 2022, STILL DOESNT WORK