SMS notification delivery is affected by your country, cellular provider, and carrier restrictions. PagerDuty does not have full control over SMS deliverability.

Push notifications are the recommended primary contact method. Push notifications are configured automatically when you log in to the mobile app. You can also add a notification rule for your mobile device. If push notifications are not a viable option, the sections below provide troubleshooting steps for SMS delivery issues.

Countries Eligible for SMS Notifications

Review Supported Countries for the full list of countries that can receive SMS notifications from PagerDuty. Confirm your country is on this list before troubleshooting further. Countries marked with an asterisk (*) indicate Partial Support due to local restrictions and regulations.

PagerDuty cannot guarantee delivery of SMS notifications to the following number types:

• Landlines, including those with Text-to-Landline (TTL) services.
• Voice Over Internet Protocol (VoIP) or virtual numbers.

Duplicate SMS Notifications

PagerDuty relies on third-party vendors to deliver SMS notifications. Those vendors rely on SMS partners and carriers to deliver messages to end recipients. PagerDuty depends on a delivery receipt from carriers and providers to confirm whether an SMS was delivered. If no delivery receipt is received, PagerDuty resends the notification. If the original notification was delivered successfully but no receipt was returned, this results in a duplicate notification.

Regulatory Policies and Carrier Restrictions

SMS content and format are heavily regulated by governments and carriers due to concerns around fraud, abuse, and aging SMS infrastructure. Vendors drop SMS messages for regulatory non-compliance and policy violations.

The list below does not represent an exhaustive or deterministic set of filtering criteria, as carriers and governments do not publish or provide feedback on their policies.

Messages Without Sensitive Content

If your SMS notifications do not contain sensitive content but are still being filtered:

• Submit a request to your mobile service provider asking them to allow all SMS messages from PagerDuty numbers. You can download the most recent PagerDuty numbers from the PagerDuty vCard.
• Use push notifications as your primary contact method.

For more information about the SMS regulatory landscape and why PagerDuty recommends switching to modern channels such as push notifications, see 6 Best Practices for Seamless Notifications with International SMS.

Other Common Causes

• Incorrect or Inactive Number
• Blocked Number
• Third-Party Apps
• Carrier Outage
• Roaming
• Mobile Device Settings

Incorrect or Inactive Number

Navigate to your user profile's Contact Information and confirm your phone number for errors or missing digits. Inactive and invalid numbers result in delivery failure.

Blocked Number

Your mobile device may have settings that block messages from unknown numbers, or you may have sent an opt-out reply such as "STOP" that blocked further SMS communications. Some carriers also restrict SMS messages from certain number types.

Third-Party Apps

Delivering SMS notifications to virtual numbers from third-party messaging apps may cause issues. During an application outage or service degradation, you may not receive messages sent to a virtual number. Send SMS notifications to your primary mobile device instead.

Carrier Outage

Check with your mobile service provider to confirm whether there was an outage or service issue at the time you expected to receive the notification.

Roaming

Before traveling, check with your mobile service provider to confirm whether there are any additional requirements or restrictions while roaming.

Mobile Device Settings

Check whether any mobile device settings prevented you from receiving the notification.

SMS Response Did Not Action the PagerDuty Incident

• Dual-Tone Multi-Frequency (DTMF) Issues
• Performing an Incident Action on an Old Notification
• SMS Notification Responses

Dual-Tone Multi-Frequency (DTMF) Issues

Dual-tone multi-frequency (DTMF) signals are the tones generated by keypad responses. They allow you to navigate menus, select options, and input information. When a signal is interrupted or unclear, unintended behavior may occur.

Performing an Incident Action on an Old Notification

PagerDuty takes a cautious approach to notifications so that older notifications do not overwrite newer incident state changes.

The following incident state changes prevent action on prior notifications:

• Escalations
• The incident is resolved
• The incident is reassigned

Once an incident changes state, you can no longer take action on it using notifications generated before the state change.

SMS Notification Responses

Due to a variety of factors, some countries may not support responding to SMS messages to acknowledge or resolve an incident, even if you can receive SMS notifications. See the full list in Supported Countries.

SMS Restrictions

• Short Code Messaging Restrictions
• Provider-Specific Issues with Short Codes
• Geographic Restrictions
• Message Length Restrictions

Short Code Messaging Restrictions

Some mobile carriers restrict messages from or to short codes. If you are not receiving SMS notifications from PagerDuty and your phone number meets any of the conditions below, contact your provider to verify that your account is allowed to receive SMS from short codes:

• Pay-as-you-go numbers.
• Any number that was pay-as-you-go and is now on a standard plan.
• Any number that is or was used by a business.

Provider-Specific Issues with Short Codes

• T-Mobile USA has a default content filter enabled. To remove the content filter, call T-Mobile and authorize PagerDuty's short code numbers: 73889, 42752, and 43105.
• If you recently upgraded your device with T-Mobile, a block may have been placed on the account that prevents it from receiving short code messages.

Geographic Restrictions

SMS URL Content Restrictions

To comply with local laws and regulations, URLs in SMS messages are replaced with the words URL redacted in the following countries:

• Malaysia
• Philippines
• Thailand

India's Do Not Disturb (DND) Registry

The Telecom Regulatory Authority of India (TRAI) maintains a Do Not Disturb (DND) registry. If your number is on this registry, it may cause issues receiving PagerDuty notifications. See TRAI's documentation at Unsolicited Commercial Communication for information about managing your contact preferences.

Message Length Restrictions

The following maximum length constraints apply by notification type:

If you use a custom Status Update Template and notice messages are truncated, update your templates to keep the message length under 450 characters.

Best Practices

Push notifications and Slack are significantly more reliable than SMS and are the recommended primary contact methods.

Staggering your notification rules may also improve SMS deliverability.