Adding Variation - Inventory Error

Hi, I’m trying to add a new variation to my listing but the min I do that, System merges the variation but shows the new one Inactive(Out of Stock) units are stranded - reason “Inventory Error”. Stock is in amazon’s warehouse since last 2 weeks.

Opened more than 13 cases reps asked to delete the listing wait for 24 hours and list again, did that too but same result. Tried the regular way and through flat file too.

Thank you.