Amazon Bedrock Playground returns ValidationException: Operation not allowed

I understand you're experiencing ValidationException errors when trying to use models in the Amazon Bedrock Playground, even with AWS-provided models. This is frustrating, especially since it was working yesterday.

Here are the most common causes and steps to resolve this issue:

Model Access Requirements: First, verify that you have requested and been granted access to the models you're trying to use. In Amazon Bedrock, you must explicitly request access to each model before you can invoke it, even in the Playground. To check and request model access:

1. Navigate to the Amazon Bedrock console
2. Go to the "Model access" section in the left navigation
3. Review which models show as "Access granted"
4. If models you need are not granted, click "Manage model access" and submit requests for the models you want to use

Model access requests are typically processed quickly, but some models may require additional approval steps.

IAM Permissions: Ensure your IAM user or role has the necessary permissions to invoke Bedrock models. You need permissions like bedrock:InvokeModel or bedrock:InvokeModelWithResponseStream. If your permissions changed recently or if you're using a different role than yesterday, this could explain the sudden issue.

Region Considerations: Verify you're using Amazon Bedrock in a region where the service and your desired models are available. Model availability varies by region, and if you switched regions in the console, you might need to request model access again in that specific region.

Service Quotas: Check if you've hit any service quotas for model invocations, though this typically results in different error messages.

Since this is affecting the Playground itself (not just API calls), the most likely cause is that model access needs to be requested or re-verified in your account. If you've confirmed model access is granted and IAM permissions are correct, you can add correspondence to your existing support case through the AWS Support Center at https://console.aws.amazon.com/support/ for further investigation into your specific account configuration.

The following section of this page is particularly important; could you please check it?

Request access to models - Amazon Bedrock

1. AWS Marketplace permissions: Your IAM role must have aws-marketplace:Subscribe, aws-marketplace:Unsubscribe, and aws-marketplace:ViewSubscriptions permissions. See Grant IAM permissions to request access to Amazon Bedrock foundation models with a product ID for details.
2. Anthropic models: For Anthropic models, you must complete the First Time Use (FTU) form before invoking the model. This requirement does not apply to Anthropic models accessed through the bedrock-mantle endpoint.
3. Valid payment method: Your AWS account must have a valid payment method configured for AWS Marketplace purchases.