One of our App Services run out of memory couple of times so we decided to upgrade them to a higher tier, P3mv3 was our target. We checked the availability on Azure, everything seemed to be OK, but the tier wasn’t listed under “Scale up” blade of the App Service Plan:

We rechecked the VM’s availability using CLI, it gave the same result: the tier should be shown.

Decided to give a try to the Azure CLI and upgrade through it, but no luck:

Finally we contacted Azure support to help us out, but their answer wasn’t promising: our Resource Group is too old and doesn’t support the needed VM. Meaning we had to recreate our Resource Group to be able to use higher tier App Services.

With the new Resource Group we were able to scale out.