out of stock on front, when it's in stock at back end

[GullPrint]

I have just set up a new website where I transfered the database from my previous website.
Then, I tried adding a new product by Add Product button.

On now at the front it shows "Out of stock". And no show for color & size configurations.
https://gullprint.com/clothing/iron-man-3-characters.html

But in admin it's "in Stock" & color & size configurations are set the same as all other items.

Than I tried to duplicate existing item - Iron Man Watercolor Marvel Superman,
https://gullprint.com/iron-man-watercolor-marvel-superman.html
and the same problem on duplicate too, front page -> "Out of stock":
https://gullprint.com/iron-man-3-characters-2.html

Looks like, after initial transfer all items, Magento 2 put all new created items by default in "out of stock" despite the fact in admin I'm setting as "in Stock".

Please help me to understand this problem.

[GullPrint]

So far there is "light in the tunnel"..

....I think I figured out how to fix the 'out of stock' nonsense, and also FINALLY got your new products to show up in the store.

For the 'out-of-stock' I just turned off 'Manage Inventory'. You *might* have to set this manually for each item (in which case an export/import might be easier).

For the items not showing (like this one: https://gullprint.com/iron-man-3-characters.html ) , I had to rebuild the indexes manually. Now, Magento is supposed to automatically run the indexers and update the contents but it doesn't look like it's been doing that for some reason. I'm going to see if I can figure out what's up with that and fix it, but at least now you can work on selling your shirts, and people can see new items as you put them up once I get the index thing working automatically....

[Dmitry_Fedyuk]

"For the 'out-of-stock' I just turned off 'Manage Inventory'. You *might* have to set this manually for each item"

There is a global (default) option for it.