Zapier integrates with Twilio, which is probably one of the most popular tools for sending automated SMSs or pre-recorded phone messages to customers amongst other communications related stuff. Generally, you won't have any problems when building zaps with Twilio, but if you are seeing errors you might not understand what you've done wrong.
In this guide, we're going to summarise some common errors and issues and what you can do about them.
When setting up a "Send SMS" action step, you required to provide a 'From Number' and optionally an 'Alphanumeric Sender ID" which will appear on the recipient's phone in place of the senders number.
You'll likely select the 'From Number' as an option from the dropdown list (which shows all the numbers you've registered in Twilio). If you're using a custom value here, make sure the number is in the E.164 format and use a "Formatter->Number->Format Phone Number" step to change it if not.
As for the 'Alphanumeric Sender ID', you need to make sure this is 11 characters or less, and only uses numbers, letters or spaces - no special characters, otherwise you'll see the above error message when you try and send.