Error : invalid BigNumber string

[InStll]

After deploying this contract // SPDX-License-Identifier: GPL-3.0

// Created by HashLips /* These contracts have been used to create tutorials, please review them on your own before using any of the following code for production. /

pragma solidity >=0.7.0 <0.9.0;

import "@openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol"; import "@openzeppelin/contracts/access/Ownable.sol";

contract SimpleNFTContract is ERC721Enumerable, Ownable { using Strings for uint256;

string public baseURI; string public baseExtension = ".json"; uint256 public cost = 0.05 ether; uint256 public maxSupply = 10000; uint256 public maxMintAmount = 20; bool public paused = false; mapping(address => bool) public whitelisted;

constructor( string memory _name, string memory _symbol, string memory _initBaseURI ) ERC721(_name, _symbol) { setBaseURI(_initBaseURI); mint(msg.sender, 20); }

// internal function _baseURI() internal view virtual override returns (string memory) { return baseURI; }

// public function mint(address _to, uint256 _mintAmount) public payable { uint256 supply = totalSupply(); require(!paused); require(_mintAmount > 0); require(_mintAmount <= maxMintAmount); require(supply + _mintAmount <= maxSupply);

if (msg.sender != owner()) {
    if(whitelisted[msg.sender] != true) {
      require(msg.value >= cost * _mintAmount);
    }
}

for (uint256 i = 1; i <= _mintAmount; i++) {
  _safeMint(_to, supply + i);
}

}

function walletOfOwner(address _owner) public view returns (uint256[] memory) { uint256 ownerTokenCount = balanceOf(_owner); uint256[] memory tokenIds = new uint256; for (uint256 i; i < ownerTokenCount; i++) { tokenIds[i] = tokenOfOwnerByIndex(_owner, i); } return tokenIds; }

function tokenURI(uint256 tokenId) public view virtual override returns (string memory) { require( _exists(tokenId), "ERC721Metadata: URI query for nonexistent token" );

string memory currentBaseURI = _baseURI();
return bytes(currentBaseURI).length > 0
    ? string(abi.encodePacked(currentBaseURI, tokenId.toString(), baseExtension))
    : "";

}

//only owner function setCost(uint256 _newCost) public onlyOwner() { cost = _newCost; }

function setmaxMintAmount(uint256 _newmaxMintAmount) public onlyOwner() { maxMintAmount = _newmaxMintAmount; }

function setBaseURI(string memory _newBaseURI) public onlyOwner { baseURI = _newBaseURI; }

function setBaseExtension(string memory _newBaseExtension) public onlyOwner { baseExtension = _newBaseExtension; }

function pause(bool _state) public onlyOwner { paused = _state; }

function whitelistUser(address _user) public onlyOwner { whitelisted[_user] = true; }

function removeWhitelistUser(address _user) public onlyOwner { whitelisted[_user] = false; }

function withdraw() public payable onlyOwner { require(payable(msg.sender).send(address(this).balance)); } }

and trying to get tokenURI i get this error:

call to SimpleNFTContract.tokenURI errored: Error encoding arguments: Error: invalid BigNumber string (argument="value", value="", code=INVALID_ARGUMENT, version=bignumber/5.4.1)

Any help will be really appreciated