Received email, may be targeted as can't find a landing page, and the link takes you to a confirmation you've registered page.
QAZN104 seems to be promo code.
Check your email, double status credits is a gold mine for status if you're planning on travelling soon.
You’re on your way to earning double Status Credits on Saver or Flex fares across eligible Qantas operated international flights with a ‘QF’ flight number.^
Here’s how to earn double Status Credits
Make a new Saver or Flex fare booking on an eligible Qantas operated international flight with a ‘QF’ flight number between 12.01am (AEST) 13 April 2019 and 11.59pm (AEST) 19 April 2019.^
Travel between 20 April 2019 and 30 March 2020.
Don't forget to include your Qantas Frequent Flyer number in your booking.
With no limit to the number of eligible flights you can book, it’s a great way to reach your next membership tier sooner.
Double Status Credits will be credited to your Frequent Flyer account up to six weeks after travel.
Most likely targeted as often with these promos, you need to register before booking to get the double credits