Need help finding old, outdated contacts in Outlook 365 on my PC

[Moondoggy]

I was using Outlook 365 on my old Windows 10 PC but I've since bought a new Windows 11 PC and I have a phantom email contact that I can't find it so I can get rid of it. The contact in question is for an associate of mine whom I sent email to but may not have had a contact created with their old email address. With Outlook 365 on my Windows 11 PC I do have a new contact for him with the correct email address but it's the old address that's appearing when I simply start typing his name in the TO field of a new email. If I press TO and bring up the address book, his contact is the only one displayed and there is only one email address within that contact. I've looked within Contact for this old address but nothing pops up so I'm not able to determine where Outlook is pulling that old email address from but it's frustrating to pull up his old address each time I create a new email message for him. Clicking on the old email address doesn't show me where this old phantom address is located so I would really appreciate having someone tell me where to look.

Thanks in advance for the help.