OpsGenie voice notifications are inconsistent.

[Irene Bykovsky]

We are setting up an incident response platform with voice, sms, and email. The rule is to notify immediately when an alert is created. Notifications via email and SMS are sent immediately. However, voice notifications are either has not been sent at all or sent 15 to 20 minutes later. Please advise. 

[Egor]

Hi Irene, 
Thanks for reaching out to Atlassian Community!

If voice notifications are delayed or not sent, this is usually caused by Notification Policies or escalation delays in Opsgenie.

To troubleshoot:

1. Check Notification Policies: Ensure that voice notifications are set to trigger immediately without delays.

2. Review Escalation Rules: Confirm that voice notifications are part of the initial escalation step.

3. Verify Contact Settings: Make sure the phone number is correct and capable of receiving voice calls.
   
   Please also see https://support.atlassian.com/opsgenie/docs/create-and-manage-notification-preferences/ 

Best Regards,
Egor