# x402 error reference

> Reference for x402 payment errors from facilitators and the official client, with the cause of each and how to fix it.

What each x402 error means and how to fix it, taken from the source of the official `@x402` packages, version 2.31. It covers the `exact` scheme on EVM chains, which is what most x402 payments use.

## Errors from the facilitator

These arrive in the `error` field of a 402 quote or the `errorReason` of a settlement, after the seller passed your payment to its facilitator.

| Code | Meaning |
| --- | --- |
| [`invalid_exact_evm_insufficient_balance`](https://x402testendpoint.com/errors/invalid_exact_evm_insufficient_balance) | The paying wallet holds less of the token than the quoted amount. |
| [`invalid_exact_evm_signature`](https://x402testendpoint.com/errors/invalid_exact_evm_signature) | The signature does not match the transfer authorization for this token and chain. |
| [`invalid_exact_evm_missing_eip712_domain`](https://x402testendpoint.com/errors/invalid_exact_evm_missing_eip712_domain) | The seller's quote has no token name or version in `extra`. |
| [`invalid_exact_evm_token_name_mismatch`](https://x402testendpoint.com/errors/invalid_exact_evm_token_name_mismatch) | The token name in the quote is not the name the token contract reports. |
| [`invalid_exact_evm_token_version_mismatch`](https://x402testendpoint.com/errors/invalid_exact_evm_token_version_mismatch) | The token version in the quote is not the version the token contract reports. |
| [`invalid_exact_evm_recipient_mismatch`](https://x402testendpoint.com/errors/invalid_exact_evm_recipient_mismatch) | The payment is addressed to a different wallet than the quote's `payTo`. |
| [`invalid_exact_evm_authorization_value`](https://x402testendpoint.com/errors/invalid_exact_evm_authorization_value) | The signed amount is not exactly the quoted amount. |
| [`invalid_exact_evm_payload_authorization_valid_before`](https://x402testendpoint.com/errors/invalid_exact_evm_payload_authorization_valid_before) | The payment authorization has expired, or expires within the next few seconds. |
| [`invalid_exact_evm_payload_authorization_valid_after`](https://x402testendpoint.com/errors/invalid_exact_evm_payload_authorization_valid_after) | The payment authorization is not valid yet. |
| [`invalid_exact_evm_nonce_already_used`](https://x402testendpoint.com/errors/invalid_exact_evm_nonce_already_used) | This exact payment authorization has already been spent or cancelled. |
| [`invalid_exact_evm_eip3009_not_supported`](https://x402testendpoint.com/errors/invalid_exact_evm_eip3009_not_supported) | The quoted token cannot be paid with a signed transfer authorization. |
| [`invalid_exact_evm_transaction_simulation_failed`](https://x402testendpoint.com/errors/invalid_exact_evm_transaction_simulation_failed) | The facilitator simulated the transfer and it failed for a reason it could not identify. |
| [`invalid_exact_evm_network_mismatch`](https://x402testendpoint.com/errors/invalid_exact_evm_network_mismatch) | The payment was made for a different network than the one quoted, or for one the facilitator does not know. |
| [`invalid_exact_evm_scheme`](https://x402testendpoint.com/errors/invalid_exact_evm_scheme) | The payment or the requirements name a scheme other than `exact`. |
| [`invalid_exact_evm_non_canonical_signature`](https://x402testendpoint.com/errors/invalid_exact_evm_non_canonical_signature) | The signature is a valid shape but uses the high-`s` form, which is rejected. |
| [`invalid_exact_evm_failed_to_verify_signature`](https://x402testendpoint.com/errors/invalid_exact_evm_failed_to_verify_signature) | The facilitator could not complete signature verification. |
| [`invalid_exact_evm_transaction_failed`](https://x402testendpoint.com/errors/invalid_exact_evm_transaction_failed) | The payment passed verification but the on-chain transfer failed. |

## Errors from the client

These are thrown by the official client before it sends any payment.

| Message | Meaning |
| --- | --- |
| [`All payment requirements were rejected by spendControls.maxAmountPerPayment`](https://x402testendpoint.com/errors/spend-controls-rejected) | The official client refused to pay because every option costs more than its per-payment cap. |
| [`No network/scheme registered for x402 version: 2 which comply with the payment requirements`](https://x402testendpoint.com/errors/no-network-scheme-registered) | The client has no wallet scheme registered for any option the seller offers. |
| [`Invalid payment required header`](https://x402testendpoint.com/errors/invalid-payment-required-header) | The client could not read the seller's quote. |

## Look one up from a script or agent

```bash
curl 'https://x402testendpoint.com/api/errors?q=invalid_exact_evm_signature'
```

Source: https://x402testendpoint.com/errors