I tried to run your solidity code with my server url and it seems to be working and the images are loading at opensea.
But, when I try the same code with your server url the images are not loading at the opensea. 
Here is the code that I used with my server url. and my metadata0, metadata1
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
contract TestContract {
// Some logic
}
//Import ERC 1155 token contract from OpenZeppelin//
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC1155/ERC1155.sol";
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/access/Ownable.sol";
contract NFTContractTest2 is ERC1155, Ownable {
uint256 public constant APICTURE1 = 0;
uint256 public constant PICTURE2 = 1;
constructor() ERC1155 ("https://0g4wexcx5qtg.usemoralis.com/{id}.json") {
_mint(msg.sender, APICTURE1, 1, "");
_mint(msg.sender, PICTURE2, 2, "");
}
function mint(address account,uint256 id,uint256 amount) public onlyOwner {
_mint(account, id, amount, "");
}
function burn(address account, uint256 id, uint256 amount) public {
require(msg.sender == account);
_burn(account, id, amount);
}
}
