@vincerap,
This can be possible only in two cases
(a) When the width and height are not set. In the screenshot, it is set so this is not the case.
(b) when you have added the custom CSS to hide these buttons. It could be possible in your case.
Also in your screenshot, the custom class is not set. Please add the custom class and then apply custom CSS on that class
Like this:
http://prntscr.com/kwhk85
Refer:
http://prntscr.com/kwhjkb
If still it will not work then paste this custom CSS in wp-admin > Appearance > Customize > custom CSS
.single-course .certificate_generated .extra_buttons {display:inline-block !important;}