The problem of restricting the display of ads on the site is one of the most important developments in Google Adsense.

A number of website owners have received messages from Google Adsense stating that ads are restricted to sites owned by the Adsense account holder.

Start of the ad serving restriction issue:

This problem and this message reached website owners in September 2019, the date on which the new Google AdSense policy entered into force.

Google Adsense told publishers in the new policy to use its program that Google will resort to a new procedure in order to ensure the quality of visits to preserve the rights of advertisers.

The new measure will be taken against sites that commit some violations that do not amount to violating the policy, by restricting the display of ads for a limited period until the origin of the problem is resolved.
Restricting ad serving means either blocking it entirely for a limited time, or reducing your number of ad units. If you use, for example, four ad units, and you are punished by reducing the number of units, you will remain, for example, one ad unit that appears, or is banned entirely, to an unspecified date.

Reason for showing ad restriction issue:

Ad restriction is mainly due to traffic quality, Google Adsense has begun to focus on quality that leads to significant conversions for advertisers.

Most of the people who got the message restricting ad serving say that they rely heavily on Facebook traffic, and their visits from Google's search engine are few.

Solve ad serving restriction issue:

Google recommends continuing to work and improving the traffic quality when arriving with a message restricting ad serving.

What you should do when reaching the message is to stop the visits that come to you from Facebook and other non-quality sources, and to work to raise the percentage of visits coming from Google search engine.

And to ensure the quality of useful and renewable content that comes with visits, Google Adsense no longer favors displaying its ads on topics that do not receive visits.

And if you notice about two years ago, advertisements start to appear late on new topics, as well as topics that do not receive any visits, even though they are old.

Google Adsense has become more strict than before, and no longer accepts clicks as they were, but has become tacitly stipulated that these clicks be valuable to the advertiser.
Stop entering your site or watching your channel, even for your family or friends who share your router or who are close to you depending on your location, this is one of the most important reasons why these viewers are considered invalid or illusory
If you subscribe to third-party services related to making viewers click on ads or cause any other misleading attempt you should stop this
Reducing visits from social media, especially if you have a lot of friends and relatives that you share with in the internet connection sometimes, this may be calculated from illegal visits, especially if your ads are clicked