Google GPT returns empty ads under which conditions

I have Google Ads integration in my NextJS app, but every now and then when I try to define a slot and load ad in it I get event.isEmpty = true for "slotRenderedEvent".

I see GPT documentation has mentioned this field here, but it does not explains uder what circumstances GPT might return isEmpty as true.

Any help is appreciated.

isEmpty=true means the adserver was not able to select an ad to display on this request. Different reasons to explain the lack of ad to show :

• no campaign / line item is currently live on your ad network.
• a campaign is live, but due to the fact that the adserver is trying to distribute impressions evenly over time, it may be "on hold" for few minutes (or more). Details here.
• campaigns are live, but none is targeting the requested inventory (adunit, device, country, daytime...etc). Details here.
• campaigns are live, but they all have a "frequency capping" that your browser reached. It is usually set to limit the number of exposure to each user. Details here.
• no house ad is live on your network : this kind of campaign is meant to fullfill the "empty" spaces so no "blank" adrequests should happens. Details here.

Following this documentation, you should be able to identify the reasons why the adrequest is returning nothing to display.

To avoid empty spaces, you can ask the adOps team to activate an house ad priorty campaign which will be called every time no "guaranteed" ad is available.