iMessage sending as Text message
Why are my iMessages sending as green Text messages only to certain iPhones? They send as a blue messages and the receiver gets the message, but 2 minutes later it turns green and says sent as text message? How do I fix this? I have signed out and back in again. Turned messaging off and back on again. I have even reset my network settings and nothing is working! So frustrating!
iPhone 5c, iOS 9.0.2