When saving a new report with many columns you may get this error: Coumns width is exceeding the maxmum width supported by Letter-Landscape. Either reduce column width or select Custom page size.
You are using too many columns for the default page size of "letter".
Choose custom page size:
- Click just above the header bar in the report preview step (ie. step 5)
- From the menu choose a custom size (see screenshot)