Error message for invalid login should not be generic

[sappaji]

When an user enters wrong credentials, error message needs to be displayed accordingly. Currently the error message states "Invalid Credentials Click Ok to get back to Login screen or Close to exit the application"

Expected Result should be based on the relevant field. eg,

1. Wrong Host Name - "Host Name does not exist"
2. Wrong User/Password - "The User Name or Password you entered is incorrect."
3. For Blank values in Host Name - "Host Name cannot be blank"
4. For Blank values in User Name - "User Name cannot be blank"

[anmolbabu]

Blank Values Handled.
The Display of Other Errors is impractical.I mean when one enters wrong login credentials in any of the sites,which credential is wrong THAT is rarely displayed as it is not SAFE.Offcourse a check for the presence of "@" in the user name is done in my latest push.