---
updatedAt: 2026-06-05T18:10:45.000Z
agentTools:
siteIndex: https://support.pagerduty.com/llms.txt
projectIndex: https://support.pagerduty.com/main/llms.txt
---
# Why Incidents Fail to Trigger
Troubleshooting common issues related to incident trigger failures
There are a few reasons why an incident would fail to trigger:
* [A Service Was Disabled or in a Maintenance Window](#a-service-was-disabled-or-in-a-maintenance-window)
* [Event Orchestration is Configured to Suppress Certain Alerts](#event-orchestration-is-configured-to-suppress-certain-alerts)
* [Email Integration Filters](#email-integration-filters)
* [Email Management Rules Were Appending Triggers to Existing Incidents](#email-management-rules-were-appending-triggers-to-existing-incidents)
* [No One Was On-Call](#no-one-was-on-call)
# A Service Was Disabled or in a Maintenance Window
When a service is disabled or in a [Maintenance Window](https://support.pagerduty.com/main/docs/maintenance-windows), new incidents are not triggered or created on that service. Because no incident is created, PagerDuty does not send notifications to the service's on-call responders.
# Event Orchestration is Configured to Suppress Certain Alerts
If you have [Event Orchestration](https://support.pagerduty.com/main/docs/event-orchestration) configured on your account, you may have rules that suppress alerts meeting certain criteria. In those cases, no incident is triggered.
Navigate to **AIOps** :fa-arrow-right: **Event Orchestration** and select the **orchestration** containing the action rule you want to check. Under **Incident Data** :fa-arrow-right: **Basic Event**, check whether the **Suppress incident and notifications** checkbox is enabled.
# Email Integration Filters
If you have regex filters set up on your email integration service, check whether your email filters are [filtering out emails](https://support.pagerduty.com/main/docs/email-management-filters-and-rules#email-filters) that you want to trigger incidents.
For example, if you have the following regex filter:
`Trigger an alert if All of the following conditions apply: The email subject matches the regular expression CRITICAL`
Emails with the subject line "PROBLEM" do not trigger incidents in PagerDuty because they are filtered out by your regex rules.
* [Regex Examples](https://support.pagerduty.com/main/docs/regular-expressions#regex-examples)
* [Test your regular expressions with Regex101](https://regex101.com/) — use the Golang flavor with the `m` and `s` flags to see exactly how PagerDuty interprets your regex.
# Email Management Rules Were Appending Triggers to Existing Incidents
Email integration settings include email management rule settings, which are separate from [email filters](https://support.pagerduty.com/main/docs/email-management-filters-and-rules#email-filters). Email filters determine which emails trigger incidents for your service. Email management rules determine how emails create new incidents.
If you have either of the following email management rules configured:
* **Open a new alert only if an open incident does not already exist**
* **Open and resolve alerts based on custom rules**
...then an incident was most likely appended to an existing incident rather than creating a new one. When a trigger event is appended to an incident, it appears in the incident's timeline. Refer to [Trigger and Resolve Alerts/Incidents](https://support.pagerduty.com/main/docs/email-management-filters-and-rules#trigger-and-resolve-alertsincidents) for more information.
# No One Was On-Call
If no one is on-call under a service's escalation policy, PagerDuty cannot assign a user to an incident and does not create a new incident.
For example, if your escalation policy only has a schedule where one user is on-call from 00:00–08:00, and a trigger event comes in between 08:01–23:59, PagerDuty does not create an incident because no one is on call during that time.
To address this issue, review the [Escalation Policy](https://support.pagerduty.com/main/docs/escalation-policies) for your service and ensure someone is on-call when incidents are triggered.
> 📘 Trigger an Incident in the Web App
>
> If you try to trigger an incident through the [web app](https://support.pagerduty.com/main/docs/incidents#trigger-an-incident-via-web-app) while no one is on-call on the escalation policy associated with that service, you receive the error **Incident could not be assigned**.