Hi ​@Leaa.

Thank you for your post. Not receiving SMS authentication codes after entering your mobile number can sometimes happen if you've recently done a number transfer. This can cause a temporary mismatch between your number and the network, which affects SMS delivery.

To resolve this, please try a network reset on your device:

For Android:

Open Settings
Tap General management
Tap Reset
Tap Reset network settings

For iPhone:

Go to Settings
Tap Phone
Tap My Number
Use the delete button to remove the old number
Use the keypad to enter the new number
Tap Save
Go to Settings
Tap Messages
Turn off iMessage
Go to General
Tap Reset
Tap Reset Network Settings
Once the iPhone restarts, go back to Settings
Tap Messages
Turn iMessage back ON

This should allow your device to recognise the new SIM/number and get it re-verified, which typically resolves the authentication code issue.

Please give this a try and let us know if you're still having trouble afterward.

Thanks,

Marquerita

The iD Mobile Team