Attachments sent for smushing but cannot fetch

Installed WP Smush Pro 1.0.3.1 on a new site (stand-alone site) and submitted a bulk smush request. The submission process came up with the usual "please wait for email" response but after that, when visiting the Smush page again, there is no status report.

No "Fetch smushed images" button visible but the button to send another request is live. However, when I click that, it responds with

"Hey there, it looks like there is a pending bulk request for this site, you can send a new one once the current request is completed."

Please find a screenshot on http://status301.net/wp-content/uploads/2015/03/Schermafdruk-van-2015-03-28-000718.png

Is this a known issue or conflict with another plugin? How can I fetch images when there is no fetch button?