@Ani Kiourktchian Firstly, apologies for the delay in responding on this and any inconvenience this issue may have caused.
Resource Manager vCPU quotas for virtual machines and virtual machine scale sets are enforced at two tiers for each subscription, in each region.
The first tier is the Total Regional vCPUs limit across all VM series. The second tier is the per VM series vCPUs limit, such as the D-series vCPUs. Anytime a new virtual machine is to be deployed, the sum of new and existing vCPUs usage for that VM series must not exceed the vCPU quota approved for that particular VM series. Further, the total new and existing vCPU count deployed across all VM series shouldn't exceed the Total Regional vCPUs quota approved for the subscription. If either of those quotas are exceeded, the VM deployment won't be allowed. You can request an increase of the vCPUs quota limit for the VM series from Azure portal. An increase in the VM series quota automatically increases the Total Regional vCPUs limit by the same amount.
You can read more about it here.
I would recommend you to contact azure support. If you have a support plan, requesting you to file a support ticket, else please do let us know, we will try and help you get a one-time free technical support.
Hope it helps :) !!!
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