License still shows invalid even after following the reinstall steps

That process (outlined in this earlier thread) covers the common single-server move case, but yours might be different — is this a multi-seat/team license by any chance, where the same key might be legitimately activated on more than one machine at once? Those work differently since the release option is disabled by design to prevent losing track of which install is authoritative. Can you confirm your license tier and whether you have any other active installs right now?

That's exactly it then — multi-seat licenses need each install registered as a separate seat rather than using the automatic single-install release flow. I'll need to add your new server as an additional seat manually on our end. Can you send over the installation ID shown on your new server's /setup/license page? I'll get that added today.