Print SSRS Report in Landscape Mode

Click on Report Properties

Set InteractiveSize to 11in, 8.5in

Set Margins to 0.5cm, 0.5cm, 0.5cm, 0.5cm

Set PageSize to 29.7cm, 21cm

Make sure dimensions of report on layout were less than or equal to (InteractiveSize + Margin Size) and (PageSize + Margin Size)

Deployed Report.

Next Recommended Reading SSRS Report generation in C#