Ok, your complaint is that printer always prints "Landscape" mode instead of "Portrait" mode normally referred to as paper "orientation".
How do you print your emails? What Browser do you use? Do you use an application like Thunderbird? If not, what application do you utilize? You say you reinstalled software, but you dont say what software?? What is your operating system (Windows 10)? Please answer all questions. What email provider do you use? Give us step by step how you are trying to print emails.
AS temporary fix, you can go to:
Control Panel -> Printers & Devices -> Right Click 4510DW Icon -> Select Printing Preferences
and you will see option to print either Portrait or Landscape. This becomes your new default.