Array
(
    [hotmail-com.olc.protection.outlook.com] => 2
    [hotmail.com] => 0
)

try hotmail-com.olc.protection.outlook.com:25

try hotmail.com:25

Error: Could not connect to a valid mail server for this email address: @hotmail.com

lindraskes@hotmail.com is invalid The email addresses you entered is not valid