There could be a couple of reasons for trouble creating a Certificate of Achievement.
If you're not doing so already, instead of a mobile device, try using a pc or laptop and use a popular browser (e.g., Chrome or some other well-known browser) to access the Canvas class and then request the certificate.
Remember, after clicking Next on the Certificate of Achievement Canvas page, you need to click on the Load Certificate of Achievement in a New Window button (image below) and then complete the form (image also below). Your browser will need to open a new window.
If you're still having trouble, don't give up! Contact us via our Ask a Librarian page. We'll be happy to help you.