Pulling Data from Messari with API key into Google Sheets

My JavaScript shows no errors in the logs but when I have input the function into Google Sheets my cell returns a blank. Here is the code:

function getFullyDilutedMarketCap(ticker) {
if (!ticker || typeof ticker !== 'string') {
return 'Error: Invalid ticker symbol provided';
}

const apiKey = 'Your Messari API key'; //
const url = https://data.messari.io/api/v1/assets/${ticker}/metrics/market-data;

const options = {
'method': 'get',
'headers': {
'x-messari-api-key': apiKey
}
};

try {
const response = UrlFetchApp.fetch(url, options);
const data = JSON.parse(response.getContentText());

    if (data.status && !data.status.error_code) {
      return data.data.market_data.marketcap_diluted_usd; // Return the fully diluted market cap in USD
    } else {
      return `Error: Ticker not recognized or API issue`;
    }

} catch (error) {
return Error fetching data: ${error.message};
}
}

function fetchFullyDilutedMarketCap(ticker) {
const marketCap = getFullyDilutedMarketCap(ticker);

const sheet = SpreadsheetApp.getActiveSpreadsheet().getActiveSheet();
sheet.getRange('A1').setValue('Fully Diluted Market Cap (USD)');
sheet.getRange('B1').setValue(marketCap);
}

Used ChatGPT to amend the code but I cannot get it to stop displaying blank cells.