Usually a red fonts displayed in a 'TO' field means the tin nhắn address you typed is not in any of your address books. It does not mean anything is wrong with the tin nhắn address. The colour is used merely to tướng draw your attention to tướng the fact it is not in an address book. However, if you have not typed it correctly that is another matter entirely.
So the fact that it is red should not have anything to tướng tự with the ability to tướng send.
So lets focus just on the sending issue. I cannot send the tin nhắn to tướng the addressee. This does not offer much helpful info. Can you offer a bit more info?
Do you see a 'Send' button? If yes, after clicking on 'Send' button what happens ? Do you see a small window saying it is sending? - mind you this can appear and disappear sánh fast if a short tin nhắn.
Is a copy put in the 'Sent' folder? Do you get an error message? If yes, what is it...word for word or post an image showing error message.
Do you get a bounced back Mailor daemon message?