Don't have access to my license

I can I get my license from my server or other machine that have license cause I can’t have access to my second seller

You need to login at and clear licence keys then reactivate on new machine.

I don’t have the access to the former license key I bought from a retailer… is it possible I get it from the server terminal

No, licences are activated via samba website system, nothing transferable is local.
Who was the reseller? What was the samba account email address shown on the top on the market page within samba on old system.