Please check following,
Click Report Properties on the Report menu, switch to the Layout tab, and set the page size and margin after calculating. Please pay attention to the following rules:
1 Body + Right margin + Left margin should be less than page width.
2 Body + Top margin + Bottom margin should be less than page height.
3 If you have header and footer take them also into account.
4 If you have any textbox, line or other data regions, please make sure whether their width large then the size of page.