The DMGuild website is the primary official source for older D&D content. Wizards of the Coast partners with them to sell past issues of Dragon and Dungeon magazines. You can search for "Dragon Magazine 411" directly on their site to purchase a high-quality PDF.
The username was Dungeon_Master_4Life . The text read: “For those looking for the rare issues, check the Annex. Link: dragon411.pdf” dragon magazine 411 pdf download