I'm not able to play Minecraft Preview without purchasing Game Pass.

Hi, TarmoPölhö my name is Jhon, and will be a pleasure help you

This issue than you have it's kinda weird because in the same words of the official minecraft page says:

On Xbox, anyone who owns Minecraft: Bedrock Edition or has a subscription to Game Pass can search for Minecraft Preview and click Install on the resulting product page – it's as simple as that! You can also find Minecraft Preview in the Xbox Game Pass library and app.

You can check it by the next link:

https://help.minecraft.net/hc/en-us/articles/4423653831821-Minecraft-Preview-FAQ

Note: This is a non-Microsoft website. The page appears to be providing accurate, safe information. Watch out for ads on the site that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the site before you decide to download and install it

Try doing this:

Ensure you're logged in with the correct Microsoft account: Make sure you're using the account that bought the Bedrock edition.

Restart your Xbox: Sometimes a simple restart can resolve issues with subscriptions and access.

Even trying the solutions i was provided to you this issue doesn't solve, i recommend to you buy the gamepass because if you have it you can play minecraft and another games than can be access with this subscription.

Best Regards. Jhon

I'm not sure how you were then without buying it or possibly with Game Pass, but you have to purchase Minecraft for each platform you'd want to play it on.

you can use any game pass subscription to play online, but if you're looking to play Minecraft as part of your Game Pass subscription without purchasing it, you require ultimate

Thank you for contact us! I'm Anderson, an Independent Consultant and a Microsoft user like you.

good afternoon

It looks like you are trying to play the Windows 10 edition of Minecraft on your Xbox, but the game is showing up as "Preview" when you launch it.

There are a few potential reasons for this:

You may be trying to play the "Minecraft for Windows 10" version of the game, which is a separate version of the game that is designed for PC and tablets running Windows 10. This version of the game is not available for Xbox and cannot be played on the console.

You may have downloaded the "Minecraft for Xbox One" version of the game, which is the console version of Minecraft that is designed for Xbox One and Xbox Series consoles. This version of the game may show up as "Preview" if you are playing it before its official release.

You may be using the Xbox Game Pass subscription service, which allows you to access a library of games on your console. If you are using Game Pass to access Minecraft, the game may show up as "Preview" until you purchase it or until the game leaves the Game Pass library.

It's being added to Game Pass for PC today so you will be able to play it for free with Game Pass. You would still need to purchase it if you want to continue playing without Game Pass.