To resolve this:
Check your file dimensions. Make sure your document is set to the correct finished size (plus bleed, if required).
Confirm resolution. For best print quality, files should typically be set to 300 DPI at full size.
Do not simply stretch the file. Enlarging a small file can reduce image quality and result in blurry or pixelated printing.
Update your design file. Adjust the canvas size in your design program and re-export the file at the correct dimensions.
If you’re unsure of the required size, review the product specifications on the order page before re-uploading your file.