Is this where you got the Key?

https://docs.microsoft.com/en-us/windows-server/get-started/kmsclientkeys

And which is to do with Volume Licensing.

To use the keys listed here (which are GVLKs), you must first have a KMS host running in your deployment.

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Or did you use this information and generic Key:

https://www.eightforums.com/threads/clean-install-windows-8.2299/

If you have a retail Windows 8 product key and want to clean install Windows 8.1 or Windows 8.1 Update, then you would need to enter a generic key below to install unactivated with, and change the product key later on in step 22 below to activate with your Windows 8 key.

Generic keys to install with:

• Windows 8 (core): FB4WR-32NVD-4RW79-XQFWH-CYQG3
• Windows 8 Pro: XKY4K-2NRWR-8F6P2-448RF-CRYQH
• Windows 8 Pro with Media Center: RR3BN-3YY9P-9D7FC-7J4YF-QGJXW
• Windows 8.1 (core): 334NH-RXG76-64THK-C7CKG-D3VPT
• Windows 8.1 (core single language): Y9NXP-XT8MV-PT9TG-97CT3-9D6TC
• Windows 8.1 Pro: XHQ8N-C3MCJ-RQXB6-WCHYG-C9WKB
• Windows 8.1 Pro with Media Center: GBFNG-2X3TC-8R27F-RMKYB-JK7QT
• Windows 8.1 Enterprise: MNDGV-M6PKV-DV4DR-CYY8X-2YRXH OR FHQNR-XYXYC-8PMHT-TV4PH-DRQ3H

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You also complicated things by using an Upgrade License from 7 to clean install.

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I suggest that you contact Microsoft: contact MS support 

Regards.

I have been using Nirsoft's ProduKey. It works with Windows 8.

ProduKey is a small utility that displays the ProductID and the CD-Key of Microsoft Office (Microsoft Office 2003, Microsoft Office 2007), Windows (Including Windows 7 and Windows Vista), Exchange Server, and SQL Server installed on your computer.

1. Create a bootable USB flash drive to install Windows 8.

2. Navigate to <FlashDrive>:\Sources\

3. Save a file called ei.cfg in that folder with the following text:

   [EditionID]
   Core
   [Channel]
   Retail
   [VL]
   0
   

If you want to install the Pro edition, replace Core with Professional. If you want the setup to ask which edition you want install without entering the product key, leave the [EditionID] blank.

You can also set [VL] (Volume Licensing) to 1 (for true) and [Channel] to OEM/Retail

Now install as normal and the Windows 8 setup won't ask for the product key. This will work for every copy of Windows 8 that you can get from anywhere.

Also, if you ever to want to enter the product key, you can do so from the Windows Activation window or using the slui 3 command.