I'm adding 3 doubleClick ads to an amp page as following with same data-slot it shows only 1 ad instead of 3, sometimes it shows 2 instead of 3 and ads not displayed shows white or same as the attached images any idea about this issue :
<div class="ad-box">
<div class="amp-ad-container">
<amp-ad width="300" height="250" type="doubleclick" data-slot="/6355419/Travel/Europe/France/Paris">
</amp-ad>
</div>
<span class="ad-text">Advertisement</span>
</div>
