Our client has reported having issues with their email signatures in web mail, particularly the images which all of a sudden stopped working. The issue started right after the SM was upgraded to the latest version: 9652. When i copy the link from the source code in the web email signature, the image links serve: 

{"success":false,"message":"No Access"}

Example: https://mail.thamesrockets.com/attachedfile?data=MbxgE6F8vRP0s5jajXB92olOZZ%2BR3v6KBhmaiT9h9MiS%2Bco8Ge0ao7YscyGuoYZU9YPXhxLz1M0%3D

Just to confirm, no changes were made to the server or SM config apart from the upgrade to v9652.