Error code 4

Device: iPhone 7
Operating system: iOS 15.7.9

I subscribed with a new Apple ID, but I wanna keep my current account in IF so I try to link it with my forum account but I keep getting error code 4

Hello!

You can’t transfer a subscription from a new account to an existing one like that.
The way to do this correctly is to be signed in before making the purchase :)

We can fix it manually though.
What is the username/callsign for the new account?

I never knew and so sorry it’s AD083A4C

It’s been transferred now :)

Yep I’m back on pro, thanks. This can be closed now