Registered CS6 upgrade license will not activate on new PC — installer validates serial, QR sign-in succeeds, app launches into expired (0-day) trial

I have a registered Photoshop CS6 upgrade license (upgraded from CS4). The CS6 serial number is visible on my Adobe account and matches what I am entering. I properly deactivated CS6 on my old PC (Help > Deactivate) before moving to a new Windows 11 PC.

On the new PC I have tried, over many attempts:

• Clean installs from multiple sources: my backup installer, the download from my Adobe account page, and finally my original purchase disc
• Full uninstall and registry cleanup between attempts
• Running the installer and the application as administrator
• Installing the Creative Cloud desktop app and signing in before installing/launching CS6
• Offline activation
• Verified correct system clock/date/timezone, no antivirus interference, no Adobe entries in the hosts file
• The new QR-code sign-in method (per helpx.adobe.com/x-productkb/global/reactivate-older-apps.html)

Current state, using the original purchase disc installer:

1. The installer accepted my serial and displayed: "Your serial number for Adobe Photoshop CS6 [English (North America)] has been validated."
2. I completed the new QR-code sign-in successfully during install ("You're signed in").
3. Installation completed normally ("These applications are ready for use").
4. On launch, Photoshop opens to a trial screen reading "Your trial will expire in 0 days."
5. Clicking "License This Software" and completing the sign-in again (successfully, every time) returns me to the same expired trial screen. Help > Activate and Help > Deactivate are both grayed out.
6. The upgrade qualifying-product prompt (to enter my CS4 serial) has never appeared in any attempt.

Everything on the client side succeeds — sign-in completes, the serial is validated by the installer itself — yet the license is never issued to the application. This appears to be a server-side failure to complete validation/licensing for my upgrade serial.

Requesting escalation or assistance activating my legitimately purchased, registered license on my new PC. I can provide the last 4 digits of the serial, screenshots of every step, and my Adobe ID via DM.