Send mail failing when sentDate configuration passed

I have just configured SendGrid plugin in my new grails app. Normal sendMail is working fine but scheduled mail was not sent. Please check my code below:

```
Date date
use( TimeCategory ) {
    date = new Date() + 2.minutes
}

sendMail {
    from "admin@test.com"
    to "laxmi@test.com"
    subject "New blog"
    sentDate date
    body "A new blog has been created on ${date}"
}
```
