Make sure Backblaze is working with Cloudflare. This can be found HERE Uncomment out the below. I made my Backblaze URL s3.DOMAIN.COM nano /etc/pleroma/config.exs # Configure S3 support if desired. # The public S3 endpoint (base_url) is different depending on region and provider, # consult your S3 provider's documentation for details on what to use. # config :pleroma, Pleroma.Upload, uploader: Pleroma.Uploaders.S3, base_url: "https://s3.DOMAIN.COM/file" # config :pleroma, Pleroma.