I bought a new Iphone 8 plus yesterday and my son set it up last night. Today I tried to send pictures to both my husband and my son which both have Samsung Galaxy phones and the message shows undeliverable. I've sent the same pics to my sister who has an Iphone and she received them. Something must be wrong in the setting, because I sent them pics on their Galaxy yesterday from my I phone 6 plus, that went trough.