Why Model Invoke Failed with "ValidationException, Operation not allowed"?

It's says Model access page has been retired now .. how can I alter the access model access now. Serverless foundation models are now automatically enabled across all AWS commercial regions when first invoked in your account, so you can start using them instantly. You no longer need to manually activate model access through this page.

Based on your error message "ValidationException, Operation not allowed" when trying to invoke Bedrock models, the most likely issue is that you haven't explicitly enabled access to the specific models you want to use. This is a common issue that occurs even when you have the correct IAM permissions and can list the models.

Here's how to resolve this:

1. Navigate to the Amazon Bedrock console
2. Go to "Model access" under "Bedrock configurations" in the left navigation pane
3. Click on "Modify model access"
4. Select the specific models you want to use
5. Submit your request and wait for approval (usually quick but may take several minutes)

Even with the proper IAM permissions and the ability to list foundation models, you still need to explicitly request access to each model you want to use. This is a separate process from setting up IAM permissions.

For some models (like Anthropic's Claude), you may need to provide use case details by filling out a form before access is granted.

You don't need to upgrade your account - this is a standard requirement for all accounts, including free tier. After requesting access, check that the status changes to "Access granted" before attempting to invoke the models again.

Also, ensure you're using a region where the specific model is available. Not all models are available in all regions - they are primarily supported in US East (N. Virginia) and US West (Oregon) regions.
Sources
Unable to invoke any Amazon Bedrock models — “ValidationException: Operation not allowed” despite full permissions | AWS re:Post
Bedrock model access | AWS re:Post