Why You See "YouTube connection is not available for this account"
When you open Connect YouTube in the App Marketplace, GRIN may show "YouTube connection is not available for this account" with the Connect with Google button greyed out. This article explains what that message means and what you can use today.
Quick answer: The brand YouTube connection is not enabled for your account. It is switched on by GRIN, not by anything in your account settings, so there is nothing for you to change and nothing you did wrong.
What is not causing it
Three things are worth ruling out straight away, because they are the usual suspects and none of them applies here.
Not your user role. The button is disabled for everyone on the account. Being an Admin does not change the screen, and no permission can be granted to unlock it.
Not your Google account or your browser. The message comes from GRIN before Google is ever contacted, so signing in with a different Google account, using a different browser, or clearing your cache will land you on the same screen.
Not something you can buy or upgrade into. This is not a plan limit, so changing your subscription will not turn it on.
What you can use today
Which of these you want depends on whether you are after your creators' YouTube data or your own channel.
To get your creators' YouTube videos and metrics into GRIN, have each creator connect their own channel from their Live Site. This is the path that feeds creator video and engagement data into GRIN, it is completely separate from the brand connection, and it is working normally. The steps are in Connecting Your YouTube Account, which you can send to your creators as is.
To find and recruit YouTube creators, use YouTube Search from Recruitment > Creator Search. See Using YouTube Search.
To see which brand-level connections you do have, review the apps listed in Using the App Marketplace.
If you need the brand YouTube connection
Contact GRIN Support and tell us what you are trying to do with your brand's YouTube channel. We will note the request against your account so we can come back to you about it. Please do not spend time reconnecting Google accounts or adjusting user permissions first, because neither affects this message.
Note: This message reflects the state of your account at the time you see it. If it changes for your account, the Connect with Google button becomes clickable and no action is needed from you to make that happen.