It is important to clear the ache of the mobile app from time to time, to keep it all running smoothly.
Also, if you cannot see your new customers within the app when trying to assign mail, clearing cache can fix this issue.
To clear the cache of the Operator mobile app, follow the below steps:
Log out of the app
When you are on the login screen of the app, click on the (?) sign in the bottom right of the screen
Click Clear Cache
Once cleared, you can return to the login screen & log back in to use the app to upload mail as normal