IPhone not sending iMessage to one person?

So I put a friend of mine on do not disturb for a day or two to keep myself from texting them. I took it off and texting was fine. I just realized that a lot of the imessages I've sent him (since Sunday) didn't deliver and they did not automatically switch to text. Why is that happening? I don't believe he would block me he s my best friend. But it is possible.

He's blocking you.

  • Why is my Iphone not sending as Imessages and receiving iMessages from one person? I'm texting my wife and we both have iPhone's and she is getting the messages as an iMessage but the ones I'm sending her on my end show up at green. Sometime it will go as blue, get the little red exclamation point then send as regular SMS. I'm texting someone else too and she has an iPhone, and she is getting mine as regular iMessages and mine are sending as regular iMessages. Why aren't they sending to me wife as iMessages?
  • Why is my iphone 4s sending texts to everyone except one person in specific? I have an iPhone 4S, I've been texting a few people today but there's this one person in specific that my phone doesn't let my message go through to them? It just randomly happened in the middle of one of our conversations when I tried to reply but all it says is "message send failure." I didn't want to, but I deleted our whole message history and still nothing.
  • Why is my IMessage sending but not delivering? I have an iPhone 4 and I'm trying to text a friend and I text them and it says delivered but then a few seconds later it says not delivered. It is doing it to only this one person and it randomly started doing this. When they text me it comes in as text. How can I fix this? What is wrong?
  • Why does my iMessage not go thru to a certain person? So when I text this one person it won't go thru as iMessage. Yes she has an iPhone and yes my iMessages are going thru to other people. When other people text that person, they go thru as iMessage. So has she blocked me or something? Or what else could it be?