When trying to create a folder in Box for Salesforce, the error "Unable to collaborate user to box folder. Error making collaboration request to Box" is thrown.
This is caused when the Box Service account does not have the necessary privileges granted on Box (Co-Admin privileges). The request is made to create the folder but the Box Service account is not privileged to add collaborators to the folder.
The Admin will need to grant the Box Service account Co-Admin privileges in their Admin Console under the "Edit User Access Permissions" section. This will grant the Box Service account the correct permissions to add collaborators to the folder.