Need authentication of Office 2016 I bought online. Any ideas?

[OBE17]

I bought it from an ad online and I upgraded all my WIN 7 computers' hard drives, so I had to clone the HDDs onto SSDs. Now I'm having trouble with authentications. I'm even getting "this copy of Windows may be illegitimate" on some of them. Nobody will even talk to me about WIN 7 stuff.

I have a half dozen machines bc whenever I had to breakdown and get the new Windows OS I would buy a refurbished Dell with the new OS on it. They all work fine; some with XP and some with WIN 7. They fly with the new SSDs. I did buy a Dell WIN 10 machine bc of the conflicts with web pages. And I bought an HP Laptop a few Christmases ago with WIN 11. BOY! I thought I hated Win 10!

I never used it; I only just hooked it up to a monitor out-here on the porch so I'm not sitting in the basement all day long. I have this Win 7 Acer laptop and the HP out here running a nice set of dual monitors I just bought. SCEPTRE 24" only $130 for the pair! Amazon. I have dual boots of Linux on each of them and I'm trying to get-the-hang-of-it.

Does anyone know a workaround for the authentication problem?