> ## Documentation Index
> Fetch the complete documentation index at: https://docs.autheo.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Common errors

> Troubleshooting guide for common errors encountered when developing on Autheo Chain.

## Transaction errors

### `signature verification failed: chain ID does not match`

**Cause**: The `--chain-id` flag is missing or set to the wrong value.

**Fix**:

```bash theme={null}
# Always include this flag
autheod tx ... --chain-id autheo_2127-1
```

***

### `insufficient funds for gas * price + value`

**Cause**: The sending address does not have enough `aauth` to cover the transaction value plus gas fees.

**Fix**:

1. Check the balance: `autheod query bank balance <address> aauth --chain-id autheo_2127-1`
2. Request testnet tokens from the [faucet](https://testnet-faucet.autheo.com/) if needed
3. Reduce the transaction amount or use a lower gas price

***

### `out of gas`

**Cause**: Gas limit set too low for the operation.

**Fix**:

```bash theme={null}
# Use auto gas estimation with a safety buffer
--gas auto --gas-adjustment 1.5
```

***

### `tx already in mempool`

**Cause**: You submitted a duplicate transaction with the same nonce.

**Fix**: Wait for the first transaction to confirm. If it's stuck, resubmit with a higher gas price using the same nonce.

***

### `account sequence mismatch`

**Cause**: The account sequence (nonce) in your transaction doesn't match the chain's expected value.

**Fix**:

```bash theme={null}
# Query the current sequence
autheod query account <address> --chain-id autheo_2127-1
```

In ethers.js, set `nonce` explicitly:

```javascript theme={null}
const nonce = await provider.getTransactionCount(wallet.address, "pending");
const tx = await wallet.sendTransaction({ ..., nonce });
```

***

## License errors

### `ErrLicenseNotBound`

**Cause**: You tried to delegate or create a validator without a bound license.

**Fix**: Bind your license first:

```bash theme={null}
autheod tx license bind <license-id> \
  --from mykey --chain-id autheo_2127-1 --keyring-backend file
```

***

### `ErrCooldownNotElapsed`

**Cause**: You tried to bind a license before the unbind cooldown expired.

**Fix**: Query the category policy to see the remaining cooldown:

```bash theme={null}
autheod query license category-policy 1
```

***

### `ErrLicenseRevoked`

**Cause**: The license has been suspended by governance.

**Fix**: The reinstatement process requires a governance action (`MsgReinstateLicense`). See [Runbook D in backups and restore](/nodes/operations/backups-and-restore).

***

## Contract errors

### `Error: VM Exception while processing transaction: revert`

**Cause**: A `require()` or `revert()` statement was triggered in the contract.

**Fix**:

1. Check the revert reason in the transaction receipt
2. Use `eth_call` to simulate the transaction before submitting:
   ```javascript theme={null}
   await contract.myFunction.staticCall(args);
   ```

***

### `invalid opcode` or `unsupported opcode`

**Cause**: Contract compiled with an EVM version higher than `paris`, which is not supported.

**Fix**: Set `evmVersion: "paris"` in your Hardhat or Foundry config and recompile.

***

### `contract not deployed` or empty response from `eth_getCode`

**Cause**: The address doesn't contain contract code — either the deployment failed or the wrong address is being queried.

**Fix**:

```bash theme={null}
curl -X POST https://rpc1.autheo.com \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"eth_getCode","params":["0x<address>","latest"],"id":1}'
```

If the result is `"0x"`, the contract is not deployed at that address.

***

## Keyring errors

### `Error: key not found`

**Cause**: The key name doesn't exist in the specified keyring backend.

**Fix**:

```bash theme={null}
# List available keys
autheod keys list --keyring-backend file

# Import a key by mnemonic if needed
autheod keys add mykey --recover --keyring-backend file
```

***

### `Error: ciphertext decryption failed`

**Cause**: Incorrect keyring passphrase entered.

**Fix**: Re-enter the correct passphrase for the `file` keyring backend. If the passphrase is lost, the key cannot be decrypted — restore from mnemonic.