Missing iMessage after flight on iPhone and Apple Watch

After a flight, my iMessages were not connected. I had to reconnect because my watch showed an important iMessage that was received but my phone did not. After resyncing to iCloud, restarting and updating and pairing both the phone and the watch, the iMessage disappeared. I don’t think signing out and back in to my Apple ID will work because it never synced to my iCloud. Is the iMessage lost for good?

[Re-Titled by Moderator]

Original Title: Missing iMessages after flight