BackBlaze announced a week ago they supports S3 API.
However, I'm unable to connect with WinSCP to BackBlaze. WinSCP comes back with following error message: "Connection failed. Invalid request parameter received: max-keys".
I made sure the API key has permission to list all buckets.
Could be user error of course, but I have no problems connecting to e.g. Wasabi with WinSCP.
Attached is the log file, hope you can see where the problems lies.
I took out the keys: I could supply them when required.