title: Send SMS with trial twilio account
body: <p>I want to try to send SMS to a cellphone in Austria. I have set up a free trial Twilio account to do so. however, my Twilio account seems not to be capable of doing so. but I think it should be possible to send SMS with the trial account?</p>
  <p>This is a screenshot of my Twilio number where you can see that it's not capable of messaging:
  <img src="https://i.stack.imgur.com/zepdQ.png" alt="enter image description here" /></p>
  <p>this is the exception i get when running my python-code which tries to send the SMS:</p>
  <pre><code>twilio.rest.exceptions.TwilioRestException: HTTP 400 error: 21606: The From phone number +43720881723 is not a valid, SMS-capable inbound phone number or short code for your account.
  </code></pre>
  <p>any idea on how I can get this running? in other words: how can I activate SMS-capability for my free Twilio account? if this is possible, what are the limitations, i.e., how many free SMS messages can I send?</p>
  <p>thanks!</p>