A vSphere 7 key will not work on vSphere 8. You must upgrade your keys through the Broadcom Customer Support Portal.
vSphere 8 Enterprise Plus License Key: Features, Licensing & Deployment vsphere 8 enterprise plus license key
Avoid using "key generators" or "leaked" keys found online. These pose a massive security risk and leave your infrastructure unsupported during a system failure. 📌 To help you get the right setup, could you tell me: Are you upgrading from an older version (like 6.7 or 7)? How many physical CPU cores do your servers have? A vSphere 7 key will not work on vSphere 8