Not working

I have downloaded the insider it keeps saying my account is authorised to play iv joined via the xbox insider hub and everything.

Hasn’t started yet

still haven’t seen anyone say they were able to play i think were all in the same boat

If you got an email earlier this week saying you’ve been accepted, now all you have to do is just got to wait for the codes to be sent out. Gameplay already seen has been from the developers playing… You should receive a code through waypoint messages later on in the day. I’ve seen rumors of it possibly being delayed until the early hours (AM) PST… So you should have your code by tomorrow.

Invites to the Halo Infinite tech preview will be rolling out later this afternoon (23rd September) [PST - this could be anywhere from 1 to 5ish hours from now] when the build becomes available for pre-loading. This will include a DM in your Halo Waypoint Message Inbox with all the links to download/install instructions on the Halo Insider Support Site and access to any Steam Keys [if applicable] on your Halo Waypoint Insider Profile [be sure and check that they are for Infinite and not MCC].

Access to the game will turn on later today allowing you to play Training Mode. Weapon Drills, explore the Battle Pass and access Customization, with the first PVP flight starting Friday, September 24 @ 10am PST

Please see the latest blog for further information:
https://www.halowaypoint.com/en-us/news/multiplayer-technical-preview-overview