I'm trying to implement the Crossmint button as per the docs here: https://docs.crossmint.com/docs/crossmint-pay-button
but I'm getting the error NFT count must be a string or number (see photo). Has anyone run into this before? Any help would be greatly appreciated.
My mint function is
  function crossMint(address _crossmintReciever, uint256 _mintAmount) public payable mintCompliance(_mintAmount) {
    require(!paused, "The contract is paused!");
    require(!allowListActive, "Public mint has not started");
    require(msg.value >= cost * _mintAmount, "Insufficient funds!");
    require(msg.sender == crossmintAddress, "This function is for Crossmint users only!");
    _mintLoop(_crossmintReciever, _mintAmount);
  }
function _mintLoop(address _receiver, uint256 _mintAmount) internal {
    for (uint256 i = 0; i < _mintAmount; i++) {
      supply.increment();
      _safeMint(_receiver, supply.current());
    }
  }
I have used both string and number format for the amount fields, and also tried a contract that uses counters to track tokenIDs and another that uses Strings