AccessDenied when opening task as worker

I set up per instructions and invited a worker. The worker can login but gets a red error message when opening the task prompting them to reload the page.

Appears to receive a 403 when creating a signed URL to the resource: https://s3.ap-southeast-2.amazonaws.com/multipagepdfa2i-multipagepdfa2i1be8d0a8-1w7g66m5qd0wi/wip/... with AccessDenied message.

The pngs do get created, but it looks like there is insufficient privileges to create signed urls.

Reproduce the worker login and task-opening flow, then inspect the signed-URL creation path and the permissions used for the generated S3 resource. Confirm the fix by opening a worker task without the 403 AccessDenied error while retaining the generated PNGs.

Written by the indexing model from the issue text.