Are my fetch parameters messing up my query?

Im getting the following error:

Failed to load resource: the api/data?small=&medium=&large=:1 server responded with a status of 503 (Service Unavailable)

Im trying to fetch from my heroku pgdb but it doesnt seem to be connecting. It works fine when I had the localhost set up. why?

    useEffect(()=>{
        Axios.get('/api/data', {params: {small:(checkedA ? "" : "small"), medium:(checkedB ? "" : "medium"), large:(checkedC ? "" : "large")}})
        .then(res=>{
            setDogList(res.data);
        })
    }, [checkedA, checkedB, checkedC])

app.get('/api/data', async(req, res)=>{
    const small = req.query.small;
    const medium = req.query.medium;
    const large = req.query.large;
    try{
        const getCity = await pool.query("SELECT * FROM dogs WHERE size NOT IN (($1), ($2), ($3)) ORDER BY breed",[small, medium, large]);
        res.json(getCity.rows)
    }catch(err){
        console.log(err.message)
    }
})