Did you specify the S3_ENDPOINT?
S3_ENDPOINT=https://gateway.storjshare.io
Perhaps S3_HOSTNAME should be
S3_HOSTNAME=gateway.darksheep.social
S3_ALIAS_HOST=gateway.darksheep.social
See also the lab with Pixelfed (for mastodon): How to set up Pixelfed on Ubuntu 22.04 connected to Storj DCS