Windows Server Datacenter 2016 in VMware Virtual Machine

Hi,

I was wondering if anyone could help me with the following problem with Windows license.

I have a VRTX with 4 blades. Each blade has a sticker with the Windows Server 2019 Datacenter (16 core) product key. We bought extra licenses for the rest of the cores in each server, so we cover all the cores for virtualisation.

We have installed ESXi to create VMware virtual machines in the 4 blades. If I create a new Virtual Machine in VMware and install Windows Server Datacenter 2016 (not 2019) on it, it asks me to activate the license. If I try to enter the 2019 product key from the sticker, then an error message appears saying it is not valid. If I try to activate the Windows Server Datacenter 2016 offline, it fails saying “Can’t Activate Windows by phone”. I have read multiple articles and pdfs about Windows licensing, but I have not seen anything related to this.

Is there a way I can activate Windows Server Datacenter 2016 in my Virtual Machine? Do I need to use a different Product Key from the sticker since this one does not work? Do I need to contact Microsoft or Dell to downgrade the Product Key from Datacenter 2019 to Datacenter 2016?

Thanks,

Cesar