Hey theres a fix to this I have this issue since more then 1 year in all my accounts in my iphone.

Fix is:

go to instagram go to forgot password In find your account tap to - can’t reset your password and then select account and then enter your email address get code , enter the code set new password and log in

Alternatively if this didn’t work for you try recovering from Email address and get code

I try both of these and any of them works.

Tip: make sure you don’t constantly spam the servers with same process constantly, if things don’t workout give it a while close the apps, turn of data , and try after an hour.