The only way I can send a text message to non - iPhone users from my Apple Watch is by switching the " send and receive " setting to only my phone number. When any of the emails are checked , I get a " message not delivered " error when I send via the Apple Watch. Is it just me , or has anyone experienced this and had to tweak these settings ? Or is your email checked and you can still send via your Apple Watch with no issues? Let me know. The Apple workers couldn't figure it out and wanted me to send my Watch in for a diagnostic. I said no and figured it out without doing that.