PagerDuty phone and SMS notifications can come from varying numbers based on your country and other variables. The best way to ensure that you’re receiving a notification from PagerDuty is to download the PagerDuty vCard, which is an up-to-date file that contains the numbers that PagerDuty notifications can come from. You can import the PagerDuty vCard into your address book on your computer or smartphone. We highly recommend downloading the vCard and keeping it updated.
If you're experiencing issues receiving SMS messages from short codes, your phone may be blocking short code messages, or your carrier may need to enable short code messaging for you.