It’s OneDrive telling you that are using too much resources, and to back off. It’s how it rate limits.
To avoid this, reduce number of threads to one.
OneDrive and DropBox don’t tolerate abuse by tools like duplicacy and others that try to use these services for bulk storage. They are designed for file sharing, not to serve as a backing store for another app. There are specialized storage services designed for that instead: Amazon S3, Backblaze B2, Wasaib are most well known examples.
You can get away with abusing the service to a degree, but you need to be careful, and use as little resources as possible, to fly under the radar so to speak.
Reducing number of threads to a minimum, and increasing average chunk size are few things you can do to minimize impact on the service.
I would not recommend using any of the *Drive type remote as backup destination to begin with - there are much better suitable alternatives readily available