Please understand that it might take up to a week to get the message. Try to get a lot of people to invite you the more invites that you get the better Your chances are at getting into the program are. There is a slight chance that Microsoft may not select you but don't worry keep trying to get people to invite You and your chances of getting in will rise.
A user contacted Microsoft about why he was not being to be invited to the preview program and this is what they had to say."Cool! Trent, I see the Invitation that came from your friend or friends, but the Preview Program is not going through because of the previous account suspension dated Sept 15 to 29, 2014. There are 2 types of category that can be part of the program. These are: Must not a Child account and no previous or existing Account Suspension from the Xbox Live Enforcement Team."
Well it looks like i was wrong if you have had an enforcement action on your account you can be invited to the program I invited my second account that had an enforcement action on it because i had a bad gamertag and they made me change it. Well 2 days later i got a message saying welcome to the preview program so maybe it is for certain enforcement actions on your account that wont let you in. Well here is some proof below.Maybe it is only for suspensions and not a gamertag change im not 100% sure.
[ Register or Signin to view external links. ]
Contact Xbox live at [ Register or Signin to view external links. ]
(bottom of the page)
by phone 18004myxbox
or go to [ Register or Signin to view external links. ]
and it will show you all your suspension you ever had on your account.
Tell them something like my friend has invited me to the Xbox live preview dashboard and I have not received it yet and I was wondering why, thank you.
If you do have any suspensions I would recommend making a new free Xbox live account and post that one and make sure it is and adult account.
If all that fails and you still cannot get in don't worry the new dashboard will be out on November 12 2015.