How are you trying to invoke the Action? Postman, localhost default app,
adobe hosted default app? There are different tips and things to check
for based on how you are interacting with it. Is this the same question
as
https://experienceleaguecommunities.adobe.com/t5/project-firefly-questions/quot-error-quot-quot-request-is-invalid-reason-failed/qaq-p/399607
?