Not sure exactly what is going on there. It looks like some webdav oddness.
I made a free adrive account and what seems to be happening is that when rclone makes a folder, it doesn’t appear to become ready for a minute or two - after that then rclone can upload to it fine. I emailled support about it.
In the mean time I note that adrive also support SFTP which rclone has a backend for - that may work better?