I cannot add my phone number

I am from Ph and i can’t add my phone number even though i put my own number there it says that the phone number is invalid. Please help me what should I do?

This is usually because the phone is a Pre-paid Mobile, and not all of these support the Phone Notification system. You can try another browser and see if that helps, but Customer Support can’t add a number as we simply get the same error you do.