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  • Status code: 429 {"error": "API rate limit exceeded"}

    The official Mantle RPC employs rate limiting to ensure stability during traffic spikes. If your particular use case involves calling the Mantle API frequently, you might run into issues that arise due to rate limiting. In case this happens, please consider connecting to third-party RPCs instead. You can find the list of available RPC providers here.

  • RPC call Error: timeout

    While calling the methods of our rpc (e.g. debug trace / get logs) to sync data from blocks, you may encounter the 'Timeout' issue, that's because the output of certain calls may be a large amount of data(due to big size blocks or large amount of logs) which may needs more time to be synced.

    So under such situations if the call lacks of timeout parameter or the default timeout settings is too low, it may result in an error of timeout. So it is recommended that you should add a timeout parameter with the call or set higher timeout parameter accordingly to solve the timeout issue.

Smart Contracts

Deployment Issues

  • Contract deploy error: "max code size exceeded."

    Set optimizer bigger. Such as:

    module.exports = {
    solidity: {
    version: '0.8.4',
    settings: {
    optimizer: {
    enabled: true,
    runs: 10000,

Verification Issues

  • Contract verification error: Hardhat found multiple contracts in the project (your MyTokenContract and the imported @openzeppelin/contracts/token/ERC20/IERC20.sol), and it doesn't know against which one you want to verify the bytecode

    If you see this error, try verifying the contract again by specifying the name of the contract that you're looking to verify. You can do this using the --contract option. Here's an example:

    npx hardhat verify --contract "contracts/MyTokenContract.sol:MyToken" --network mantleTest 0x3A2b26...

Contracts Call Issues

  • Error: Failed to send transaction. Context: (code: -32000, message: failed to forward tx to sequencer, please try again. Error message: 'intrinsic gas too low', data: None)

    The reason for this error is insufficient gas fee. Although Foundry can automatically estimate gas, two things should be noted when using it:

    1. Set the priority-gas-price to 0.
    2. Set the -g parameter to 400,000 (minimum value).

Standard Bridge

  • Error when withdrawing: no bridge found for token pair

    Try switching to a different RPC provider.


  • Error: Awaiting internal transactions for reason

    You may encounter this error if you there are multiple internal transaction calls in the contract being invoked. This does not necessarily mean the transaction has failed, just that the explorer is yet to receive acknowledgements for all the internal transactions.