next.js: Functions are not valid as a React child - reactjs

Question

i trying to use react-countdown for my page and it worked although there are a few notes like react-dom.development.js:88 Warning: Functions are not valid as a React child. This may happen if you return a Component instead of <Component /> from render. Or maybe you meant to call this function rather than return it.
here my full code
import Head from 'next/head'
import React from "react"
import Countdown from "react-countdown"
import {Container, Button, Row, Col, Form, FormControl, InputGroup} from 'react-bootstrap'
class Home extends React.Component {
render() {
// Random component
const Completionist = () => <span>You are good to go!</span>;
const styleCol = {
textAlign: 'center',
color: 'grey',
fontSize: '82px',
fontWeight: 600,
display: 'grid',
fontFamily: 'VERDANABOLD'
}
const styleColSpan = {
color: 'white',
fontSize: '16px'
}
// Renderer callback with condition
const renderer = ({ days, hours, minutes, seconds, completed }) => {
if (completed) {
// Render a complete state
return <Completionist />;
} else {
// Render a countdown
return (
<>
<Col style={styleCol} className={style.clockFrame} lg={3} md={12} sm={12} xs={12}>{days} <span style={styleColSpan}>DAYS</span></Col>
<Col style={styleCol} className={style.clockFrame} lg={3} md={12} sm={12} xs={12}>{hours} <span style={styleColSpan}>HOURS</span></Col>
<Col style={styleCol} className={style.clockFrame} lg={3} md={12} sm={12} xs={12}>{minutes} <span style={styleColSpan}>MINS</span></Col>
<Col style={styleCol} className={style.clockFrame} lg={3} md={12} sm={12} xs={12}>{seconds} <span style={styleColSpan}>SEC</span></Col>
</>
);
}
};
return (
<>
<Container fluid style={{backgroundColor: 'rgba(186, 205, 214, 1)'}} className={style.mainFrame}>
<Row style={{margin:'auto', paddingTop:'40px',
justifyContent:'center'}} className={style.clockFrame}>
{renderer}
<Countdown date={Date.now() + 100000} renderer={renderer} />
</Row>
</Container>
</>
)
}
}
export default Home
in chrome and firefox browsers, the function works.
enter image description here
but in safari return NaN.
enter image description here
anyone can help me please ?