Amazon Nova models returning "ValidationException: Operation not allowed"

The “ValidationException: Operation not allowed” error encountered when invoking Amazon Nova models in Bedrock signifies that your account no longer has the necessary permissions to access these models, despite their status being listed as ACTIVE. This issue stems from policy or access control restrictions rather than the operational state of the models. AWS has recently updated its model access framework, and Nova models now require explicit account‑level enablement before they can be used.

https://docs.aws.amazon.com/bedrock/latest/userguide/troubleshooting-api-error-codes.html

https://repost.aws/questions/QU7GzcJIIDTU2jqnWZ9tWFoA/bedrock-error-validationexception-operation-not-allowed