It is called qiniu which is a Chinese cloud service provider.
https://www.qiniu.com
The problem is caused by cdn?
here is my setting:
## S3 storage
DISCOURSE_USE_S3: true
DISCOURSE_S3_REGION: whatever
DISCOURSE_S3_ENDPOINT: http://s3-ap-southeast-1.qiniucs.com
DISCOURSE_S3_ACCESS_KEY_ID: *************
DISCOURSE_S3_SECRET_ACCESS_KEY: *****************
DISCOURSE_S3_CDN_URL: http://qiniu.pengfeima.cn
DISCOURSE_S3_BUCKET: qiniu-s3
DISCOURSE_S3_BACKUP_BUCKET: qiniu-s3/backups
DISCOURSE_BACKUP_LOCATION: s3