When text messages are sent to a landline phone number they will error, but these are still chargeable messages.
We offer an additional service to validate all phone numbers as mobile prior to attempting to send a text message. By confirming a phone number as being a mobile number, you will save money not attempting to send text messages to landline phone numbers.
The cost for each number validation is $0.01 USD, and is turned on at the account level.
How to Turn on Phone Number Validation
1. In Sakari go to Account Settings
2. Turn on the Validate Phone Number Type option