How to send a message to a locked MacBook?

Question

Computer networks

I sold my MacBook Air earlier that year. Everything was fine. Today I went to my iCloud and I see this computer. And also the inscription

I did not block him. Maybe they rearranged or updated the system and asked for some kind of password from the account. Although I installed the system with the buyer and did not ask for anything. How to contact him? And is it real?
What for? It was just a good guy, and it’s not difficult for me to say the password or untie it there, I don’t know what is needed.

Answer 1

You can remove the lock simply by removing the computer from Find My iPhone using the link below.
https://support.apple.com/en-us/HT201441