Hi @LMJ ! Thank you for reaching out to the Klaviyo community with your question.
The most likely reason that you are not seeing “Device unreachable” under failure type options is because none of your collected SMS numbers have triggered that event yet (which is good!) meaning you have not sent any SMS messages to any devices that failed due to the device unreachable reason.
For now, you should be able to manually type in ‘device unreachable’ in the field to add that filter to your segment and still include it, even though it is not in the auto drop down. This will ensure the option is included in your exclusion segment for any future SMS numbers that fail due to the device unreachable reason even though there are likely not any right now in your account.
Let me know if this helps, and if you have any other questions please do reach back out!
Thanks so much! I still wasn’t able to manually type in the “failure type equals,” but I was able to manually type the “device unreachable.” I will keep an eye out and monitor the list if I do get any devices that failed due to the device unreachable reason.