Recently encountered error below when deploying a new SharePoint Server 2019 Small Farm High Availability (HA) with SQL Managed Instance.
Root cause was Azure Region. Selected “US North Central” which doesn’t offer that feature as of today (04/19/2020). Selecting different region resolved.
Below is a quick reference table showing which US Azure data centers offer SQL Managed Instance, for planning future deployment. Cheers

Supported Data Centers

Error
{“code”:”DeploymentFailed”,”message”:”At least one resource deployment operation failed. Please list deployment operations for details. Please see https://aka.ms/DeployOperations for usage details.”,”details”:[{“code”:”Conflict”,”message”:”{\r\n \”status\”: \”Failed\”,\r\n \”error\”: {\r\n \”code\”: \”ResourceDeploymentFailure\”,\r\n \”message\”: \”The resource operation completed with terminal provisioning state ‘Failed’.\”,\r\n \”details\”: [\r\n {\r\n \”code\”: \”ProvisioningDisabled\”,\r\n \”message\”: \”The deployment request failed because it would exceed total number of vCores (8) and/or subnets (1), which is above the allowance for your subscription: max vCores: 0, max number of subnets 0. Please send the support request to extend the quota using Azure portal: http://aka.ms/sql-mi-obtain-larger-quota \”\r\n }\r\n ]\r\n }\r\n}”}]}
Screenshots


Context Diagrams



