what does 2127 error message mean?

I think that's an invalid number, got it a while ago cause I didn't have the area code in my contacts

"...usually the 2127 invalid destination indicates that you should check your number and try again. It could be if number sending to has text blocked, a network issue, or not sending to a full 10 digit phone number...if you are sending text to a contact in your phone make sure contact saved has all 10 digits with area code save and also in contact make sure saved as a mobile number and not a home number..."