Purchased Xbox Live Gold but can not play online games

The games you have purchased can be played at least as long as there are no online games that require the Xbox live gold subscription

Xbox Live Gold is ONLY required for playing online Multiplayer, participating in parties and getting and playing the free Games with Gold games.

If you purchased a game digitally, you can download that without a Gold membership. You'll just be unable to play the online multiplayer part (if the game has online Multiplayer).

I purchase a Xbox live gold subscription for 12 Months

And i played online with it(I think on the begginig of March),but some days later i can’t play online again!

It appears to me i can pick up the games and play the Xbox one games FROM gold,but i don’t can play online

You need a Gold Subsciption to Xbox Live to play online multiplayer. Xbox has two types of Live servce Xbox Free and Xbox Gold, Free subscription will not allow you to play online. You can purchase a Gold Subsciption through the Xbox Marketplace from the
Xbox Dashboard.

You can purchase XBox Live by turning on your XBox One and purchasing a subscription in the Microsoft Without XBox Live, you will not be able to play XBox One Xbox Live Gold games but you will be able to keep your XBox 360 XBox Live games. Your XBox One
will still be online and most XBox 360 and XBox One apps will still function, but online play will be extremely limited.