# VoIP Callout Errors

**URL:** <https://forum.inductiveautomation.com/t/voip-callout-errors/107022>\
**Category:** Ignition\
**Created:** [June 4, 2025, 2:24pm UTC](https://forum.inductiveautomation.com/t/voip-callout-errors/107022 "2025-06-04T14:24:19Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Zayne\_Luker](https://avatars.discourse-cdn.com/v4/letter/z/74df32/32.png) [@Zayne\_Luker](https://forum.inductiveautomation.com/u/Zayne_Luker)\
**Post date:** [June 4, 2025, 2:24pm UTC](https://forum.inductiveautomation.com/t/voip-callout-errors/107022/1 "2025-06-04T14:24:20Z")

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Hello all,

I've been encountering an issue with Voice Notifications where the **Alarm Notification Profile** remains registered but fails to send alarm callouts, returning **403 errors**.

When the **VoIP system** stops working, we receive an **Agent Syntax error** , indicating that the domain provided by IT is an **unknown host** (see attached image). Once this error occurs, all subsequent callouts fail and continue returning a **403 error** , despite the Alarm Notification Profile still appearing as registered with the VoIP host.

 ![syntaxerror](https://us1.discourse-cdn.com/inductiveautomation/original/3X/e/c/ec4c02becf5e748a68febd8d57daecb6b3793c99.png)  
 ![callerrors](https://us1.discourse-cdn.com/inductiveautomation/original/3X/1/b/1bce12dd4b3987fce0dddd850140b6c8ce863817.png)

We were given a domain for the gateway address, and so far, I have tried flushing the **DNS** , but the issue persists.

Could this be a permissions/authentication issue, hence the reason we are returning 403 errors?

Has anyone else experienced this, or does anyone have troubleshooting suggestions? Any insights would be greatly appreciated!

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**Author:** ![paul-griffith](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paul-griffith/32/37249_2.png) [@paul-griffith](https://forum.inductiveautomation.com/u/paul-griffith)\
**Post date:** [June 4, 2025, 3:38pm UTC](https://forum.inductiveautomation.com/t/voip-callout-errors/107022/2 "2025-06-04T15:38:46Z")

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"No such host is known" is 100% a DNS issue in your local environment.  
~~Yell at~~ talk to your IT department.

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**Author:** ![michael.flagler](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/michael.flagler/32/26272_2.png) [@michael.flagler](https://forum.inductiveautomation.com/u/michael.flagler)\
**Post date:** [June 4, 2025, 4:08pm UTC](https://forum.inductiveautomation.com/t/voip-callout-errors/107022/3 "2025-06-04T16:08:32Z")

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It's always DNS.  
At a new plant now, and since they're using static IPs everywhere, I told them to just use the IPs rather than DNS names for things, and the guys at the plant wanted to use DNS because it just looks prettier. I told them that if/when domain controllers go down, get updates and reboot, etc it could cause issues/outages if DNS can't be resolved and that by not using domain names it removes a failure point. They agreed and we're now using IPs instead.

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**Author:** ![uqofedusiqi989](https://avatars.discourse-cdn.com/v4/letter/u/b3f665/32.png) [@uqofedusiqi989](https://forum.inductiveautomation.com/u/uqofedusiqi989)\
**Post date:** [September 25, 2025, 1:18pm UTC](https://forum.inductiveautomation.com/t/voip-callout-errors/107022/4 "2025-09-25T13:18:21Z")

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I had a similar issue and fixed it by making sure the Gateway Network was fully synced and the voice alarm profile communication settings matched the network interface actually handling SIP traffic.