Created items in admin not visible in admin

[DmS]

Hi, I'm new with Aimeos, but not new to PHP & coding.

After setting up aimeos without demo-content and the ai-sites marketplace according to https://github.com/aimeos/aimeos-laravel I'm now starting to configure things via admin & super user using the manual as a guide.

I'm getting multiple unexpected odd errors in admin when I'm trying to create things which makes me think I've missed something.

First I've setup some sites as children of default, they are visible and editable in the locales->sites
That seemed to go well.

But trying to switch between them under "sites" gives the error:
"Aimeos\MShop\Locale\Exception
Locale item for site "mercatino" not found
https://dinsaluhall.test/admin/mercatin ... ?locale=en"

Also, trying to setup Categories from scratch allows me to create them, and list them, but when trying to select them in admin I'm getting errors like "Error
Item with ID "3" in "catalog.id" not found"

In the frontend however, the category is visible.

Same happens with products, I can create a product in the default site, with both a success message and an error similar to "Error Item with ID "6" in "product.id" not found" and it's not visible in lists in admin, and of course not editable since I can't find it. Looking in the database i see it as enabled and with "siteid 1." which I guess is the default site

I'm at loss here.
Any help would be very appreciated!
/Dan

[DmS]

Right, after rebuilding the index tables after running php artisan aimeos:setup as instructed in the marketplace readme, I can now switch between sites in admin.
I still can't edit created categories or see/edit created products

When selecting a category for edit (it's found when searching for it)
"Item with ID "3" in "catalog.id" not found"

After creating a product (where I have no categories to select for it) and getting article created successfully, I get this:
"Item with ID "5" in "product.id" not found"