**Sandbox was working** with the identical schema until January 9, 2026 morning - **Started failing** January 9, 2026 - no changes made on my side -- Any update on this? Blocking our development.

[joylin2024]

Environment information

System:
  OS: Windows 11 10.0.26200
  CPU: (14) x64 Intel(R) Core(TM) Ultra 7 155U
  Memory: 8.64 GB / 31.45 GB
Binaries:
  Node: 20.19.4 - C:\nvm4w\nodejs\node.EXE
  Yarn: 1.22.22 - C:\nvm4w\nodejs\yarn.CMD
  npm: 10.8.2 - C:\nvm4w\nodejs\npm.CMD
NPM Packages:
  @aws-amplify/auth-construct: 1.8.1
  @aws-amplify/backend: 1.16.1
  @aws-amplify/backend-cli: 1.8.0
  @aws-amplify/backend-data: 1.6.1
  @aws-amplify/backend-deployer: 2.1.3
  @aws-amplify/backend-function: 1.14.1
  @aws-amplify/backend-output-schemas: 1.7.0
  @aws-amplify/backend-output-storage: 1.3.1
  @aws-amplify/backend-secret: 1.4.0
  @aws-amplify/backend-storage: 1.4.1
  @aws-amplify/cli-core: 2.2.1
  @aws-amplify/client-config: 1.8.0
  @aws-amplify/data-construct: 1.16.3
  @aws-amplify/data-schema: 1.21.1
  @aws-amplify/deployed-backend-client: 1.8.0
  @aws-amplify/form-generator: 1.2.4
  @aws-amplify/model-generator: 1.2.0
  @aws-amplify/platform-core: 1.10.0
  @aws-amplify/plugin-types: 1.11.0
  @aws-amplify/sandbox: 2.1.2
  @aws-amplify/schema-generator: 1.4.0
  @aws-cdk/toolkit-lib: 1.1.1
  aws-amplify: 6.15.5
  aws-cdk-lib: 2.211.0
  typescript: 5.9.2

Describe the bug

Sandbox deployment suddenly started failing with "Limit on the number of resources in a single stack operation exceeded" error.

The same schema was deploying successfully to sandbox until 2 days ago. Production deployment still works with the same schema.

Reproduction steps

Steps to reproduce

1. Run npx ampx sandbox
2. Deployment fails during CloudFormation stack creation

What I've tried

• Deleted sandbox and all CloudFormation stacks
• Cleaned up SSM parameters
• Deleted .amplify folder
• Waited overnight (rate limit reset)
• Same error persists

Additional context

• Schema has ~48 models with authorization rules
• Production deployment works fine
• Sandbox was working with identical schema last week
• No changes to schema between working and failing

Is there a recent change in how sandbox generates CloudFormation resources?

[pahud]

Hi @joylin2024,

Thanks for reporting this issue with detailed environment information. This is a frustrating situation, especially when the same schema works in production.

What's happening:

The error "Limit on the number of resources in a single stack operation exceeded" indicates you're hitting CloudFormation's 500 resource limit. With 48 models and authorization rules, the generated resources (DynamoDB tables, AppSync resolvers, IAM roles, etc.) can easily approach or exceed this limit.

Why it might have started failing:

1. A recent package update may have changed how resources are generated
2. Sandbox mode may generate resources differently than production (which likely uses nested stacks)
3. The resource count may have been right at the edge of the limit

Questions to help diagnose:

1. Did you recently run npm update or change any package versions?
2. Can you share the exact error message from the CloudFormation console?
3. How many authorization rules do you have per model on average?

We'll investigate whether there's been a change in resource generation that could explain the sudden failure.