[Your Block] saved to Quote category should have at least one text element.
To save a Quote block, you need to be sure that the proper element is incorporated into the block. To do this, simply go into the Quote block you’re trying to save and click on the + button to open up the Elements page. From here, click on the Elements category and add the text element to your block.
Note: The audio element comes with 1 EM of padding all around, but you can adjust that in the Margin & Padding option of your layout panel. Make sure to adjust your design to ensure a cohesive aesthetic across your page.