I have an iPhone 5S that is having trouble sending SMS messages to one of my contacts (only one) on the AT&T network. This contact has a Samsung Galaxy S4 and this problem has only started occurring within the last two weeks. Previously, this contact could receive all SMS messages from me except photo messages, which I assume is because AT&T has a cap for receiving that is smaller than Verizon's. At first, I thought it might be an issue on my contact's carrier, but this person can receive messages from all other Verizon contacts. In addition, I have another iPhone 5S for work that I texted my contact from, and they received all of those messages. So I am concluding that the issue must be on my end. How can I resolve? When I pull my Verizon call log, the messages are listed as "Sent". None of the messages have been received by my contact. I don't have any other issues sending to others with iPhones or Samsung Galaxy on Verizon, Sprint, or AT&T, just this one phone number. I have deleted my contact, reset my network, and turned iMessage on and off in an attempt to try to fix, but none of these have worked.
