Prevent text messages from being sent to recipient's email address

Recently when I sent a message to an iPhone recipient, it was sent via SMS, presumably because one of us couldn't connect to iMessage. However, the strange thing is that my iPhone sent the text message to the recipient's email address, instead of their phone number:

(I was surprised to see this actually worked because Verizon evidently relays SMS-to-email from [email protected], and when the recipient responds, it gets relayed back via SMS.)

The phone number and email address are in the correct fields in their Contacts card, but Messages chooses the email address instead of the phone number for Text Message:

I checked other contacts, and all of them have a phone number in the Text Message field in Messages, but a few have two Text Message fields, one with a phone number and one with an email address. This is the first time I have seen Messages send via email. Does anyone know of a fix?

Solution 1:

The sender needs to attach their number to their iMessage "Send & Receive" list.

On the iPhone they can go to Settings -> Messages -> Send And Receive -> Add iPhone phone number along with their Apple ID email.

Then make sure the phone number has a check mark next to it.

Then try texting them again and see if it emails them the message, it shouldn't.