Missing text messages

You may try some of these steps, please check after each step...

1. Ensure that your iPhone is connected to a stable network, whether it's Wi-Fi or cellular data. Sometimes, messages might not sync properly if there's a weak or unstable connection.
2. Check Message Settings:
   1. Go to Settings > Notifications > Messages and ensure that notifications are enabled.
   2. Also, check the "Show Previews" setting. If it's set to "When Unlocked" or "Never," try changing it to "Always" to see if it affects your notifications.
3. Check Message Filtering:
   1. If you're using the "Filter Unknown Senders" feature, some messages might be filtered out. Check the Messages app for a separate list of unknown senders.
4. Sometimes, a simple restart can resolve temporary software glitches. Turn off your iPhone, wait for a few seconds, and then turn it back on.
   1. Restart the device. That's it.
   2. Still not solved --> Force restart iPhone - Apple Support
5. If the issue persists, you can try resetting all settings on your iPhone. This will not erase your data but will reset all personalized settings to their default values. Go to Settings > General > Transfer & Reset > Reset > Reset All Settings and confirm the action. Note that you will need to reconfigure your settings afterward. All settings—including network settings, the keyboard dictionary, the Home screen layout, location settings, privacy settings, and Apple Pay cards—are removed or reset to their defaults. No data or media are deleted.
   1. Reset All Settings: Return iPhone settings to their defaults - Apple Support:- Return iPhone settings to their defaults
   2. You can return settings to their defaults without erasing your content.
   3. If you want to save your settings, back up your iPhone before returning them to their defaults. For example, if you’re trying to solve a problem but returning settings to their defaults doesn’t help, you might want to restore your previous settings from a backup.
6. Make sure you have the latest updates installed.
   1. Update Over-the-Air (OTA) —> Update your iPhone or iPad - Apple Support (IN)
   2. Update using iTunes/Finder —> Update your iPhone, iPad, or iPod touch - Apple Support (IN)

If none of the above steps resolve the issue, it is recommended to reach out to Apple Support or visit an authorized service center for further assistance. They can provide specific guidance based on your device model and iOS version.

You may not be under the All Messages section of the messaging app. You also may have a filter installed. In either case, tap the "<" icon on the top left-hand side.

Please watch the GIF below to understand both