Access login window verification code 1

Private Sub login_Click()
If IsNull(Me.username) Then
MsgBox "Please enter your username!", vbExclamation
ElseIf IsNull(Me.password) Then
MsgBox "Please enter your password!", vbExclamation
ElseIf key1 = DLookup("password", " user", "Username = '" & Me.username & "'") Then
DoCmd.OpenForm "Login interface" 'Open the login interface
Else
MsgBox "Incorrect password!", vbExclamation
End If
End Sub