Halo Infinite Code

I have opted in and signed up for the multiplayer preview awhile ago, but have yet to receive a code. What should I do? Did I miss a step in the process?

Thanks!

Also in the same boat here! Received a notification that I’ve been invited to the flight but have no message with a steam code.

I haven’t got a key myself, signed up a long time ago…I did get the Xbox version, but not the PC steam key.