That’s when IG thinks that you’re using automatization. You’re most likely getting asked to confirm your phone number. You should use one which has never been linked to an IG.
If I already used one that linked to IG something can happen?
For me those became disabled. I got them back after a day via the recover forms, but it’s better to use a totally new number.
You think I should change the number I putted into a new number (After I already approved twice with the old number)?
Than I would personally use the old number. But haven’t had a situation like that myself.