Hi,
You can use AJO's Built-in Alerts: Navigate to the Alerts section in AJO under the Administration menu. Here, you can subscribe to alerts related to API call failures. Alternatively, you can Configure Custom Alerts: You can set up custom alerts for specific API call failures. This involves creating a custom action in your journey that checks for a response from the AEP endpoint. If no response is received, the custom action can trigger an alert.
The below exp league documentation can help:
https://experienceleague.adobe.com/en/docs/journey-optimizer/using/reporting/alerts
Hope this helps