what to do when my messenger app was just keep on loading?

Hello xxyuki,

Thank you for reaching out in Apple Support Communities. To troubleshoot the Messenger app, we encourage for you to follow these steps:

1. Close and reopen the app

Force the app to close. Then open the app to see if it works as expected.

2. Restart your device

Restart your iPhone or restart your iPad. Then open the app to see if it works as expected.

3. Check for updates

To see if updates are available for the app, open the App Store, tap your profile icon, then scroll down to see if updates are available. If updates aren't available for the app, update the software on your iPhone or iPad.

4. Delete the app, then redownload it

Delete the app. When you do this, you might lose data that was stored in the app. Then redownload the app. Then check to see if the problem with the app is fixed.

These steps are relevant to the behavior you're experiencing and are outlined here for you to reference: If an app on your iPhone or iPad stops responding, closes unexpectedly, or won’t open - Apple Support

Best regards.