iMessage issue

[SayCheese]

I've just had an iMessage cone through. It pinged on my Apple Watch series 2 but the message apparently doesn't exist when I go to look at it on my phone. I go to that contacts message thread and there's only the last message I sent them but not the reply that I can read on my watch.
Any ideas what's happening or how to fix it?

 

[BugeyeSTI]

Sign out out of iMessage on both devices and sign back in and see if it that straightens it out