[iMore Question]

Pictures and videos will not send to one person. They all come back as "not delivered" or they appear to send from my phone but the other persons phone just keeps trying to download. Why? How do we fix? Which phone is the issue?

[kataran]

From what your wrote it appears that the receivers phone is the issue

Tell the person to check and see if his service provider is not having any connection issues

[iCricket]

Did the person used to have an iPhone and then switch to android or turn off iMessage? Sometimes your device will still think that they are still using an iDevice. When In fact they aren't anymore.