All characters are legit - so it was wrong lead.
But I suspect now it might be related to impersonate option in config:
You will have to use your own App (setting your own client_id and client_secret) to use this option as currently rclone's default set of permissions doesn't include "members.read".
Do you have this permission enabled? Or you just did what Get your own Dropbox App ID section of doc ask?
Switch to the Permissions tab. Enable at least the following permissions: account_info.read, files.metadata.write, files.content.write, files.content.read, sharing.write. The files.metadata.read and sharing.read checkboxes will be marked too. Click Submit