Homebrew Attunement Items don't show up

I have a problem with homebrew items that use attunement. I have checked the box in creation, that the item requires attunement but after I equip it, I can't attune to it.

Does anyone know a fix for that?

Changes to homebrew stuff can take a while to show up on an active character. Have you tried just going back to it again after a while?

It does not matter if there is time between. I already tried that including muplitple times refreshing the site and wating over a day.

And it's definitely not applying the effects of the item without it being attuned? As if it hadn't saved properly? Just want to cover all troubleshooting bases.

It did not even though it was properly. It works know, whyever, but a friend of mine has the same problem so it seems to be a bug, that sometimes shows up, when you create such an item.