Add sender to SMS via app Messages

My code

set phoneNumber to “+33681229536”
set smsMessage to “Hello”

tell application “Messages”
set myService to 1st service whose service type = iMessage
set myBuddy to buddy phoneNumber of myService
send smsMessage to myBuddy
end tell

I receive the message but I have this warning
“L’expéditeur de fait pas partie de vos contacts - Indésirable”
“The sender is not among your contacts - Junk”

The phone number is the first phone number of me in my Contacts Book

and when I delete the message from my iPhone I have this warning:

“Supprimer cette conversation comme courriel indésirable en l’envoyant à Apple”
“Delete this conversation as spam by sending it to Apple”

Two Choice :
“Indésirable - Ne pas signaler”
“Junk - Don’t report”

How to not have this warnings?

Model: MacBook Pro
AppleScript: 2.8.1 (183.1)
Browser: Safari 537.36
Operating System: macOS 10.11

Choose an entry from your Contacts app by clicking the downward-pointing arrow in the lower-right corner of the Add Buddy window. The person’s name turns up instantly in your buddy list.

You must register your phone number by signing into iMessage from your iPhone. If you are already signed into iMessage on the iPhone, sign out and sign back in on the iPhone.
If it still doesn’t appear on the computer, sign out of iMessage there and sign back in. It should appear then.

Also, in order to send SMS messages from the computer, you must enable it on the iPhone. In iPhone settings, open iMessage. Select Text Message Forwarding. You must be on the same wi-fi network. Your computer or other device should show in the list. Just click on the device you want to enable.
Also enable SMS on the iPhone.

Then run your script again.