Why is iMessage not available?
My wife and I have identical iPhones (5C) that use the same carrier. At home, we use the same WiFi network. I rarely send a message that does not go via iMessage—that is, that does not display as blue. However, it seems my wife rather often finds that her phone wants to use SMS—the message goes out green. Sometimes, she'll send a message that "goes green," while I—sitting in the same room—send a message that goes blue.
What gives? She hasn't changed any settings (not intentionally, anyway). I once told her to turn off her phone and restart, which she did—the next message went with iMessage (blue). Another time, she went to her Settings and turned off iMessage, then turned it back on. That worked.
Still, we both wonder why this switch to SMS occurs. What could she be doing—inadvertently, perhaps—to cause her phone to use SMS instead of iMessage? Might she have a problem with her phone?
iPhone 5c, iOS 9.2.1
