What does message send failure mean on iPhone? - 1

I sent this person a iMessage and it didn't go through and said "message send failure". I've texted this person before and had no problems but now it's saying this. The person I'm texting also has an iPhone. What does "message send failure" mean? Could it mean that there phone is off?

Make sure your Wi-Fi is working, it could be that

Try resetting your network settings

If you are not connected to the internet or cellular data it won't send

You need to go to settings and enable the send as text button.IPhone's use the apple i message app, so it will try and send it thru i message by default. But if the other person is a android user it can sometimes not get thru. Btw it is Settings/Messages swipe the sms to on.

How do i make a new one then