Hello,
Since your VLSC access has expired, but you possess the valid Authorization Number and License Number, you must contact the Microsoft Volume Licensing Support Center directly via phone for your specific region. Provide the support agent with your Authorization and License numbers. They are the only ones authorized to verify your ownership manually and generate or retrieve the specific Product Key for you without VLSC portal access.
You can find the up-to-date regional phone number by using a search engine to look for: "[Your Country/Region] Microsoft Volume Licensing Support Phone Number".
I am happy to follow up if you encounter any errors during execution.
If this explanation helps clarify the retrieval process and upgrade path, please click Accept Answer. This will also help other users to see the complete troubleshooting process. Thank you!