Hi,
I am pretty convinced it ultimately comes down to this: https://www.sharetribe.com/community/t/wrong-aws-signature-version-used-when-uploading-to-s3/1800
I’m no Ruby developer and am currently not able to get the sourcecode updated to use the right signature, so I decided to skip the whole AWS upload. I’ve mounted the images directory to a separate (non-aws) cloud storage, because I really do not want them on my production server.