Unable to use toMail from my notification

[abhiburk]

Hey please guide me for this
I am using default notification mail function as given below but it never gets called now Please help me out of this. I have my own content in rate_your_experience mail blade file but that is not being use.
Check my screenshot this is what my email is looking in Inbox which should not look like. rate_your_experience blade file has my custom content,

It seems that my markdown template is not in use when triggering email using below syntax.

public function toMail($notifiable)
{
    return (new MailMessage)
            ->subject("Rate Your Experience")
            ->markdown(
                'emails.rate_your_experience',
                [
                    'source' => $this->source,
                    'user' => $notifiable
                ]
            );
}