An Azure relational database service.
You may try following checks:
- Resource provider registration - In Subscriptions then your subscription then Resource providers, find Microsoft.Sql. If it isn't Registered, click Register, wait a few minutes, and reload the create page.
- Allowed-locations policy - In Policy then Assignments, look for "Allowed locations." If it's there, open its Parameters to see which regions are allowed, and create both the server and its resource group in one of those regions.
- Region access for your subscription - Some subscriptions can't create SQL servers in certain regions, which shows up as a "does not have access to create a server in the selected region" error. Try a different region, or open a support ticket to request access.
To find out which one it is, run this in Cloud Shell (the >_ icon):
az sql server create -n <unique-name> -g <rg> -l <region> \
--admin-user <user> --admin-password '<password>'
It will either create the server or return the exact error, and that error points to which of the three causes applies.