Hardhart simple storage - ProviderError: Must be authenticated!

[Daemonicc]

require("@nomiclabs/hardhat-waffle")`
require("dotenv").config({})

// This is a sample Hardhat task. To learn how to create your own go to
// https://hardhat.org/guides/create-task.html
task("accounts", "Prints the list of accounts", async (taskArgs, hre) => {
  const accounts = await hre.ethers.getSigners()

  for (const account of accounts) {
    console.log(account.address)
  }
})

// You need to export an object to set up your config
// Go to https://hardhat.org/config/ to learn more

const RINKEBY_RPC_URL = process.env.RINKEBY_RPC
const PRIVATE_KEY = process.env.PRIVATE_KEY
/**
 * @type import('hardhat/config').HardhatUserConfig
 */
module.exports = {
  solidity: "0.8.8",
  defaultNetwork: "hardhat",
  networks: {
    rinkeby: {
      url: RINKEBY_RPC_URL,
      account: [PRIVATE_KEY],
      chainId: 4,
    },
  },
}

that is the code of my hardhard.config but when i try to deploy on rinkeby, i get a ProviderError: Must be authenticated!

[Daemonicc]

Fixed, I mistakenly added an extra character in my URL in the .env file