Using older version of SK on new computer

I want to use SK2018 on my new MiniMac OS Monterey. I have a MacBook 2017 and a MacBook Pro 2012. I scrubbed the MacBook Pro 2012 but didnt remove my SK license #. I can use SK2018 and SK2021 on MacBook 2017, but only SK2021 on my MiniMac. When I try to use SK2018 “licensed to: SK Pro 2018 User Expired” and “This SK pro license was created on a different computer and will not work here”. Also notes “Bummer, it looks like youre offline”…yet I am online.
I’ve tried my old license numbers but a window says “The license you added is not a valid SK 2018 license” even though I copied the number on my MacBook 2017. I’d be glad to upgrade to the latest pro subscription to use the old version (I don’t like that LO2021 won’t render pdfs in vector and other strange features) if that will solve the probem, but there must be a way for this to work.