Questions to ask:

• What is the file type?
• Where were the drawings produced from? i.e. from another software?
• Does the PDF open in the expected orientation in a local desktop PDF reader?

Explanation:

• Quite often PDFs can be displayed in a PDF reader in landscape mode even when their original underlying orientation is portrait (and then the original orientation shows up in Drawboard Projects).
• Best workaround is to prevent rotation in the authoring software (i.e. print to PDF in the correct orientation) or use other software to rotate the PDF before uploading to Drawboard Projects.