I need to upload a file to a new list item in Sharepoint Online from a clientapp. The list exists allready, but I create new list items and tried to upload file as attachements. I tried it over CSOM, but failed because the attachment folder for this item doesnt exist. It'll be created only if you manually upload something...
I think the same error happens if I try to upload the file over SOAP.
Upload to an existing list item with attachements is no problem at all.
Does anybody know how to solve this issue? Is there a workaround maybe?