title: Firebase SMS Verification on iOS - 'Token Mismatch'
body: <p>When attempting to beta test my application with some external users, none of them could properly enter the app using the phone number sms verification. The developers could all use the application when built directly from Xcode, but anyone who installed via a link could not use it. </p>
  
  <p>Each user attempting to sign in / sign up would get an error readout of <code>Token Mismatch</code> - with no other info.</p>
  
  <p>I have a valid production APNS certificate, why is this not working??</p>