Common errors

Symptom

Status returns TIMED_OUT after ~30 seconds.

Cause

The RPC provider took too long to respond during fork initialization, or the transaction requires too many state lookups.

How to fix

• →Switch to a paid RPC endpoint (Alchemy, Infura, or Ava Labs archive node)
• →Check that the network field is set correctly — common mistake is using "arbitrum" instead of "arbitrum-one"
• →Try reducing the complexity of your transaction batch

Symptom

HTTP 429 response from the API.

Cause

The free tier allows 500 simulations per month. Either you have exceeded that, or you are sending requests faster than 1 per second.

How to fix

• →Add a delay between requests if you are testing in a loop
• →Upgrade to the Pro plan for 10,000 simulations per month
• →Check your current usage on the dashboard

Symptom

Error message: "Fork initialization failed" or "Unable to connect to RPC".

Cause

The public RPC endpoint is overloaded, rate-limited, or temporarily unavailable.

How to fix

• →Wait 30 seconds and retry — public RPCs have burst limits
• →For Avalanche: use https://api.avax.network/ext/bc/C/rpc or an Ava Labs-provided archive node
• →For Arbitrum: use https://arb1.arbitrum.io/rpc or a dedicated Alchemy endpoint
• →Check the status page at https://arbisimguard.vercel.app/status

Symptom

HTTP 400: "Unsupported network: <value>".

Cause

The network field in your request uses an unrecognized string.

Symptom

HTTP 401: "Invalid or revoked API key".

Cause

The API key is missing, malformed, or has been revoked.

How to fix

• →Check that you are sending the key as the X-API-Key header (not Authorization: Bearer)
• →Verify the full key including prefix: ask_free_a1b2_...
• →Generate a new key from the dashboard if yours was lost