Robb. Knight.

For the past few days, every iMessage I sent would warn me that it had not been delivered, even though I knew it had. I try restarting my iPhone and turning iMessage off and on neither of which worked. Then I realised the problems had only been happening since I installed Messages Beta for Mac. as far as I can tell, the problem lies with my Mac sending messages from my email address and my phone sending from my phone number. As soon as I uninstalled Messages, everything worked perfectly again. To uninstall Messages Beta, simply open the app and select "Uninstall Messages Beta" from the main menu. Hopefully this should help other people having the same issue.