Run tab Simulate returns 401 per-IP blocking on mainnet (wallet submit still works)

[WGB5445]

Summary

On explorer.aptoslabs.com (mainnet), using the account Modules → Run tab, clicking Simulate fails with HTTP 401 from the Aptos fullnode simulate endpoint. Write / submit via a connected wallet (e.g. OneKey) can still succeed because it uses the wallet's own RPC, not Explorer's API client.

Covers FEAT-MODULES-001 (Run sub-tab).

Steps to reproduce

1. Open https://explorer.aptoslabs.com (mainnet).
2. Connect a wallet.
3. Navigate to an account with Move modules, e.g. /account/<address>/modules/run/<module>/<function>.
4. Fill entry function arguments and click Simulate.

Expected

Simulation returns success/failure from Move execution (gas, abort, etc.).

Actual

Simulation Failed
Request to [Fullnode]: POST https://api.mainnet.aptoslabs.com/v1/transactions/simulate failed with status: (code:401) and response body: "Unauthorized: Rejected due to a per-IP blocking rule for this application"

Technical notes

• Simulate path: RunContractForm.handleSimulate → sdkV2Client.transaction.simulate.simple → POST /v1/transactions/simulate with Explorer getApiKey() / Settings API key override (app/pages/Account/Tabs/ModulesTab/Contract.tsx, app/global-config/GlobalConfig.tsx, app/lib/constants.ts).
• Write path: useSubmitTransaction → wallet signAndSubmitTransaction (does not use Explorer's Aptos API key).
• Likely causes: invalid Settings → API Keys mainnet override, missing/invalid Authorization on the simulate request, or API Gateway per-IP policy for the application client ID—not a Move simulation logic error.

Environment

• Network: mainnet
• Site: production explorer.aptoslabs.com
• Wallet submit: OK; Simulate only: fails with 401

[WGB5445]

Tracked in Linear: https://linear.app/aptoslabs/issue/DVR-161/run-tab-simulate-returns-401-per-ip-blocking-on-mainnet-wallet-submit