Thanks. That took care of that error of one error. I then got an access denied error. But upon further review of the advanced settings I was able to select signature version 2 and it works.
In the latest canary build I have added a check that sets this option automatically if the server url is not a known Amazon S3 endpoint. The advanced option --s3-ext-forcepathstyle can still override this automatic setting, but it should now work without setting it.