Find My won't release my computer, asks for an Apple ID that I changed e-mail for

I have a special situation where I changed the e-mail address of my Apple ID from erik.zivkovic@example.com to erik@example.com. After a few years I now need to pass on my computer to a colleague because I am getting a new one. The problem is, I wiped the computer clean and handed it to my colleague, but "Find My" is still attached to my old computer and my colleague can't sign in completely. When he's about to sign in using Apple ID the computer says:

Title: Apple ID Password

Enter Apple ID password for "erik.zivkovic@example.com" to turn off Find My Mac.

That's my old Apple ID e-mail address! But neither my old nor my new Apple ID passwords work to get past that screen. What can I do to unstick "Find My" from the old computer?