Node.js captureException not working

I am new to Sentry

Installed sentry

in my express Js, configured Sentry with DSN and debug, I see the sentry is initalized
Sentry Logger [Log]: Integration installed: InboundFilters
Sentry Logger [Log]: Integration installed: FunctionToString
Sentry Logger [Log]: Integration installed: ContextLines
Sentry Logger [Log]: Integration installed: Console
Sentry Logger [Log]: Integration installed: Http
Sentry Logger [Log]: Integration installed: OnUncaughtException
Sentry Logger [Log]: Integration installed: OnUnhandledRejection
Sentry Logger [Log]: Integration installed: LinkedErrors
Sentry Logger [Log]: Integration installed: RewriteFrames

but in my error handler when I say captureException, nothing shows up on Sentry
even though It is getting called

    Sentry.captureException(new Error('test exception'));

not sure why???
My sentry screen is blank