If you see a "waiting for network" message on your Facebook Messenger app (or any other app for that matter), then this probably means the app has made a request to the server - such as asking what to show in your feed or which images it needs to create the feed etc... And the app hasn't received the response it was expecting yet.
Depending on what OS you're running, this may even cause the app to close down or crash.
How to solve a "Waiting for network" problem
Although it does depend on what's causing the network problem, here are some common things you should try:
- Double check that you are still connected to the internet
- Make sure you have the latest version of the app and your operating system installed
- Go into your settings, find Facebook Messenger, and then choose the "clear all data" option.
Cear the cache on both Facebook Messenger and the main Facebook app, uninstall them, delete any remaining files if you're on Android, and then resinstall both.
- Try to enforce proxy settings