LFG on companion app can be very spotty some days it works great somedays it doesnt work great, me personally I will have some instances where the people sending me invites will have trouble, then they will send me a message either on my respective platform or through the in app messaging system that is a good alternative to if the app is not working hope this was helpful

Hey there! You will want to delete your app cache by going to Settings > App Settings > Delete Cache as well as Delete Content Database so it refreshes the app. Otherwise, you can do a full uninstall and reinstall of the app.