Currently, whenever the user attempting to upload an attachment/image/picture to a Whiteboard doesn't have the Add attachments space permission the upload fails with:

"Failed to Upload Try again"

Ideally, this error message should be less misleading and indicate that the upload failed or is not possible at all because the end user in question doesn't have the Add Attachments space permission on the space where the Whiteboard was created, either directly or as part of a group: