Ensure the Bamboo agent service has "Write" permissions to the folder where it's trying to download the artifact.
The user or group triggering the deployment must have "View" permissions on the original build plan to retrieve its artifacts. bamboo artifact download not working
Search for the build key (e.g., PROJ-PLAN-JOB). This will show if the server encountered a database lock or a file system error while trying to serve the file. Ensure the Bamboo agent service has "Write" permissions