Express routes not sending response Heroku-Postgres code H12 - node.js

Question

I'm having an issue with my routes not sending responses to the frontend. I only have 3 routes so far, only two send responses, but neither are doing so. I am using node-postgres(pg). My register route seems to be working because when I register a user, it is reflected in the database. Here are the two routes in question.
// login
app.post('/api/v1/login', checkInput, async (req, res, next) => {
console.log(req.body)
try {
// find user
db.query(`SELECT * FROM users WHERE username = $1`, [req.body.username], async (err, user) => {
if (err) throw err;
// user not found
if (!user) {
res.send({message: 'error'});
} else {
// compare passwords
const matchedPassword = await bcrypt.compare(req.body.password, user.password);
// password doesn't match
if (!matchedPassword) {
res.send({message: 'error'});
} else {
// user found
req.session.user = user.username;
req.session.auth = true;
res.send({message: 'success'});
}
}
})
} catch (error) {
next(error);
}
});
// register
app.post('/api/v1/register', checkInput, async (req, res, next) => {
console.log(req.body)
try {
// check if user already exists
db.query(`SELECT username FROM users WHERE username = $1`, [req.body.username], (err, user) => {
if (err || user) {
res.send({message: 'error'});
}
});
// user doesn't exist so create user
// encrypt password
const salt = await bcrypt.genSalt(3);
const hashPassword = await bcrypt.hash(req.body.password, salt);
db.query(`INSERT INTO users (username, password) VALUES ($1, $2)`, [req.body.username, hashPassword], (err, user) => {
if (err) {
res.send({message: 'error'});
} else {
res.send({message: 'success'});
}
});
} catch (error) {
next(error);
}
});
Any help would be appreciated!