Azure Container Registry (ACR) is a managed, private Docker registry service that allows you to build, store, and manage container images and artifacts. Microsoft provides three service tiers for ACR - Basic, Standard, and Premium - each offering different capabilities and performance features.
According to the Microsoft Azure Administrator documentation, Private Link integration is only available in the Premium tier of Azure Container Registry. Private Link enables you to connect to Azure services (like ACR) through a private endpoint in your virtual network, ensuring that traffic between your virtual network and the registry remains entirely within the Microsoft backbone network. This prevents exposure to the public internet and significantly enhances the security of image pull and push operations.
In the Standard and Basic tiers, ACR only supports access through public endpoints, optionally restricted by IP firewall rules or service endpoints. To configure Azure Private Link, the registry must first be upgraded to Premium tier, after which you can create a Private Endpoint associated with your registry.
Once upgraded, you can configure network rules, DNS resolution, and endpoint connections under the ACR's networking settings to fully implement private access to the registry.
Thus, the verified and Microsoft-documented answer is to upgrade the container registry to the Premium tier before configuring Azure Private Link.

Explanation:

Box 1: 60
One alert per minute will trigger one email per minute.
Box 2: 12
No more than 1 SMS every 5 minutes can be send, which equals 12 per hour.
Note: Rate limiting is a suspension of notifications that occurs when too many are sent to a particular phone number, email address or device. Rate limiting ensures that alerts are manageable and actionable.
The rate limit thresholds are:
SMS: No more than 1 SMS every 5 minutes.

Voice: No more than 1 Voice call every 5 minutes.

Email: No more than 100 emails in an hour.

Other actions are not rate limited.

References:
https://github.com/MicrosoftDocs/azure-docs/blob/master/articles/monitoring-and-diagnostics/monitoring- overview-alerts.md