I noticed that my little vanilla JS script to get people to connect to my "dapp" works fine on desktop with metamask, but doesn't work with metamask mobile app.

It gives me an error as if the "Provider" was not set.

const provider = new ethers.providers.Web3Provider(window.ethereum);
const signer = provider.getSigner();
const connectbtn = document.querySelector('.connectbtn');
connectbtn.addEventListener('click',enabler);

async function enabler(){
    
        try {
  await ethereum.request({
    method: 'wallet_switchEthereumChain',
    params: [{ chainId: '0x38' }],
  });
} catch (switchError) {
  // This error code indicates that the chain has not been added to MetaMask.
  if (error.code === 4902) {
    try {
      await ethereum.request({
        method: 'wallet_addEthereumChain',
        params: [{ chainId: '0x38', rpcUrl: 'https://bsc-dataseed.binance.org/' /* ... */ }],
      });
    } catch (addError) {
      // handle "add" error
    }
  }
  // handle other "switch" errors
}
 doing();
 
};

async function doing() {
    await provider.send("eth_requestAccounts", []);

    
    
    let addressconnected = document.querySelector(".addressConnected") ;
    addressconnected.innerHTML =`Connected`;
    

    // console.log("Account:", await signer.getAddress());
}