Mongoose.connection.on listeners not working

Working with Data Node.js Frameworks
,
1

Hello,
I think listeners are not working for me.
When I put this code in program

(async () => {
    await mongoose.connect(DBTOKEN).then(() => {
        console.log("Connected to Database");
    }).catch((err) => {
        console.log("Not Connected to Database ERROR! ", err);
    });
})();

I’m getting Connected to Database. But when I use

mongoose.connection.on("connected",......
mongoose.connection.on("err",.....

I’m getting nothing.