Why is my number not working

Hi annalise117,

Thanks for contacting Apple Support Communities. The guidance below can help resolve this cellular issue:

"Before you begin

• Learn what to do if you get an error message that says "No SIM" or "Invalid SIM".
• Check the list on the System Status page. If the box by iOS Device Activation isn't green, try to activate your iPhone or iPad later.
• If asked to enter your password as you activate your iPhone or iPad, enter the password. (A password prompt means that Activation Lock might be enabled in Find My iPhone.)

Follow these steps 

1. Restart your iPhone or iPad.
2. If you're using a cellular-data connection, connect to a reliable Wi-Fi network instead.
3. If you get an error message on your iPhone or iPad that says the activation server is temporarily unavailable or cannot be reached when trying to activate, wait a few minutes, then repeat the previous steps.

If you still can't activate your iPhone or iPad, try again using your computer instead:

1. Make sure that you have the latest version of macOS or the latest version of iTunes.
2. Check that your computer has an internet connection.
3. With the cable that came with your iPhone or iPad, connect your iPhone or iPad to your computer. Locate your device on your computer.
4. Wait while your computer detects and activates your iPhone or iPad: 

• If an alert appears that says "Set up as New" or "Restore from Backup," it means your iPhone or iPad is activated.
• If you get an error message on your computer that says that the SIM card isn't compatible or is invalid, contact your carrier.
• If you get an error message that says the "activation information was invalid" or "activation information could not be obtained from the device," use recovery mode to restore your iPhone or iPad.

If you still can't activate your iPhone or iPad, contact Apple Support.

"

If you can't activate your iPhone or iPad (Wi-Fi + Cellular) - Apple Support

Cheers.