You need to have added and successfully verified test phone numbers in your account before you will be able to receive test SMS messages. Submitting test messages to a destination other than the test phone numbers registered will return a simulated response that emulates what the response will look like in your system.

You can add a maximum of three test phones to your account. To add a test phone, navigate to My Workspace --> SMS and select Manage Test Phones. Test phones can also be set up as part of the new integration wizard.

If you have added at least one test phone to your account, a Test Phones card is added to the My Workspace tab. Select this card to add, view, update, or remove test phones in your account. Note that if your test phone has an "Unverified" status (i.e., has not been verified successfully), you will not be able to send messages to this phone number and have to remove it before trying to add it again.