Missing messages in conversation might happen if your phone is disconnected or unstable. Make sure your phone is charged and connected all the time for a smooth experience.
Usually, if your phone was disconnected for a while, incoming messages during the offline time should come in once the connection is back. In a rare occasion, however, there might be a case where those messages are not loaded in Inbox or there's a delay of synchronization.
⚡ Fret not, if it happened, you can sync conversation by following these steps:
This can be used as a method to get conversation history between you and the customer as well!
Hope it helps!