Please try and login using the same credentials on the web and see if you get the same problem. It could either mean that the Android App does not have permissions to connect to the internet using via Mobile Data. You need to allow the App to use the Mobile Data App. If thats not the case it could be that you typed one character incorrectly especially when you copy and paste, you might have space before or after the username and password. It is always better to type it out.