The element will be hidden, and the page will be displayed as if the element is not there. https://www.w3schools.com/css/css_display_visibility.asp
Similar to the CSS property `display:none`, the `hide()` jQuery method also hides the selected elements. Hidden elements will not be displayed at all. https://www.w3schools.com/jquery/eff_hide.asp
This negatively impacts viewability which advertisers are held as an important metric when buying impressions.
Step 1: Check random pages if this error still pops up.
Step 2: Right click on the page > Inspect.
Step 3: Click the box with the cursor icon to select elements on the page.
Step 4: Look for the ad unit in question and click on it.
Step 5: Under the ‘Elements’ tab, you should see the “Styles” section.
Step 6: Look for anything that says `display:hidden` or `display:none` or ` .hide()`
Step 7: Once confirmed, advise the publisher to stop using it on ad unit divs.
Step 8: If the publisher refuses to do as advised, remove the ad unit from the configuration; or create a separate configuration without the hidden ad unit in it and provide implementation instructions to the publisher.