An app I'm working on has an "offline mode" - as it is frequently used in environments where mobile data is unavailable. When they're connected to the internet and login to an account, that account has offline information stored to the device so it can be logged into when the have no internet access.
The users of the app are park rangers and inspectors, so I want to make sure the language used is clear as it might show whilst they're doing their job in the field and won't be able to call anyone.
The purpose of the error messsage is to show:
When their username isn't found on the device and can't connect to the server to check for new users.
This is currently what I've got:
Username not found and unable to connect to server. Confirm username is correct or ensure server is connected to check for new user accounts.
Although I'm unsure if this is clear enough to be usable (not to mention long winded).