Trouble solving: Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client

Question

I'm working on a simple web app using node-pg and express.js with a login page and a dashboard that displays some data from a database.

The dashboard and all it's data loads fine initially using the following function after the user inputs their username and password:

const queryLogin = (request, response) => {
    var username = request.body.username;
    var password = request.body.password;
    
    if (username && password) {

        Promise.all([
            pool.query('SELECT * FROM jobdesc WHERE complete=0 AND customer=$1 ORDER BY date_rec ASC LIMIT 10', ['somecustomer']),
            pool.query('SELECT * FROM accounts WHERE email=$1 AND password=$2', [username, password],)
          ]).then(function([orderResults, results]) {
            if (results.rows.length > 0) {
                request.session.loggedin = true;
                request.session.username = username;
                var user = username;
                var orderObj = orderResults.rows;
                if (results.rows[0].account_type == 1) {
                    request.session.account_type = 1;
                    response.render('pages/index');
                } else if (results.rows[0].account_type == 0) {
                    request.session.account_type = 0;
                    response.render('pages/dashboard', {
                        user: user,
                        orderObj: orderObj
                    });
                } else {
                    console.log("Invalid Account Type");
                }
            } else {
                response.send('Incorrect Username and/or Password!');
            }           
            response.end();
          }, function(error) {
            throw error;
          });
        
    } else {
        response.send('Please enter Username and Password!');
        response.end();
    }  
}

The issue is that I have a link in my navbar that redirects to the dashboard (in the case that the user navigates to a different page and wants to return to the home page). When pressed I get the following error: Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client

The route I use to try and redirect to the home page is: app.get('/home', con.launchDashboard)

And the code for the function is:

const launchDashboard = (request, response) => {

    if (request.session.loggedin) {
        Promise.all([
            pool.query('SELECT * FROM jobdesc WHERE complete=0 AND customer=$1 ORDER BY date_rec ASC LIMIT 10', ['somecustomer'])
        ]).then(function([orderResults]) {
            if (request.session.account_type == 1) {
                return response.render('pages/index');
            } 
            else if (request.session.account_type == 0) {
                var user = request.session.username;
                var orderObj = orderResults.rows;
                
                return response.render('pages/dashboard', {
                    orderObj: orderObj,
                    user: user
                });
            }
        })
    } else {
        response.render('pages/login');
    }
    response.end();
}

I'm unsure of why I am getting this error, I am confused with where I am setting headers after they are sent to the client.