This task can be performed using Fileping
Your Real-Time Autoresponder for Dependency Downtimes
Best product for this task

Fileping
dev-tools
Monitor and Automate Your Support Responses During Third-Party Downtimes: FailPing Effortlessly Keeps Your Users Informed

What to expect from an ideal product
- Automatically detects when external services are down
- Sends pre-written responses to users without manual intervention
- Keeps customers informed about issues beyond your control
- Reduces support team workload during service disruptions
- Customizes messages based on specific third-party outages