Photos. Why aren't they able to send?
When I attach a photo and I tried with different people and different photos, I receive a can not deliver! Message.
Hello,
Check your network connection. To send a message as iMessage or MMS, you need a cellular data or Wi-Ficonnection. To send an SMS message, you need to have a cellular network connection. If you have Wi-Fi Calling turned on, you can send SMS messages over Wi-Fi. Contact your carrier for more information.
More info here:
If you can't send or receive messages on your iPhone, iPad, or iPod touch - Apple Support