If you landed on this page you are definitely managing a Woocommerce store & having trouble with WordPress Woocommerce product variations.
Here’s the quick solution I’ve found. The error “This product is currently out of stock and unavailable” comes when you don’t assign product prices on each product variation.
Remember next time. Whenever you get the error you just have to click on the Variations tab on the product data section and expand each variation section with the little dropdown arrow and then give whatever the price you need under each variable.
Hope you have resolved your issue. Don’t forget to share.