This makes sure your Smart SIM connects to use data services. You only need to update the field called 'APN' - please leave all other fields as they are
Open Settings
Tap Network & Internet or Connections
Tap SIMs or Mobile network
Select your Smart SIM
Tap Access point names
Select the '+' in the top right
For Name, put in 'Smart SIM'
For APN put in '
data00.telnyx'Leave the rest blank and tap Save
Ensure this APN is selected