Missing iOS iMessage showing in OSX Messages This is the second time this has happened to me in the past couple of days so it starts to bother me: somebody sends me an iMessage, that I never get on my iPhone (4S iOS 8.2) but I do get on my Macbook's (OS 10.10.2 Yosemite) Messages application (v8.0). Even days later the messages are not appearing on my iPhone.

Do you have any idea why this is happening and how I could manually force a synchronization?
It can happen if your phone is outside good reception area for iMessage - carrier signal dropped to GPRS/Edge etc. 

The Mac picks it up, the system considers it delivered.
There is no further attempt to send it to your phone.

It used to happen to me a lot when I was working in a low-reception area.

It won't re-synchronise.

See How to tell Messages &quot;I&#39;m not at home&quot;? for a similar experience.

It doesn't happen if your phone is set to airplane mode, or off altogether. For some reason, that will trigger a delivery of missed messages when you switch back on again.

[All of this may be mobile-operator influenced - I've never been able to figure that part out - whether it happens to everyone or just certain carriers.]