I'm trying to use newer Anthropic models, including anthropic.claude-opus-4-8, through bedrock_runtime and bedrock_mantle, but my account receives an AccessDeniedException saying the model isn't available and suggesting that I contact AWS Sales. I'm seeing the same restriction with GPT 5.6 models. I opened a support case four days ago, but it is still unassigned. I've also seen others report similar problems, so I'm trying to understand whether this is an account approval issue, an IAM permissions issue, a regional availability limitation, or something else. What is the correct way to request access or escalate this?
4 Answers
IAM permissions alone may not be enough. Access to individual foundation models can require an account-level approval or availability flag, so check whether an administrator has enabled the models for the account and region you’re using.
An access-denied response that immediately rejects the request is different from a normal support delay, especially when there’s no documented appeal path. I’d continue the support case with the precise error and model IDs, while preparing a direct-provider fallback if access is time-sensitive.
If you don’t specifically need Bedrock, using Anthropic’s or OpenAI’s direct APIs may be the fastest workaround. That avoids Bedrock’s account approval process and model availability flags, though it means managing another provider and billing setup.
It sounds like the newer model families may not yet be enabled for your account. A support case is probably the official route, although an unassigned case after several days is understandably frustrating. Make sure the request clearly lists the exact model IDs, account, region, and whether you’re using runtime or Mantle APIs.
I had a similar issue with the Anthropic 5-series and OpenAI 5.6 models. My case was eventually closed without a useful explanation, so I’m considering using Azure or going directly through the model providers instead.

I’ve already granted the IAM user broad Bedrock permissions, including the full-access and Mantle-related policies, but the models are still unavailable. That makes it seem more like an account-level restriction than an IAM problem.