# Which Problems Are Solved
If a notification channel was not present, notification workers would
retry to the max attempts. This leads to unnecessary load.
Additionally, a client noticed bad actors trying to abuse SMS MFA.
# How the Problems Are Solved
- Directly cancel the notification on:
- a missing channel and stop retries.
- any `4xx` errors from Twilio Verify
# Additional Changes
None
# Additional Context
reported by customer