I have an iPhone 8. I send and receive text messages with others who have iPhones and others who have other brands of phones. With everyone who has an iPhone I believe I receive a sound alert when I receive a text. However, I have recently noticed that when my wife's nurse sends me a text from her Samsung I get no audio notification. I only now I have received a message by turning on the phone to see if the message icon is showing a number notification. Today I checked Settings; and the alert was, indeed, selected. I went ahead anyway and changed the alert sounds. Tested it with the nurse immediately, and it still didn't work. Her Samsung does set off the alert on my MacBook Air, but will not set off the iPhone. Ideas?