If Google finds any invalid clicks or any other issues, they might take further enforcement action or your account might be permanently disabled. It's your duty to keep your website compliance with the AdSense Program Policies.
On 24th of November 2019, I received mail for saying
I found a few reasons which might have caused the Google Giant to warn me by not allowing the ads to be shown on my website.
Adlimit message is a warning only not disapproving your account.
I do not use the Cloudflare to store my website on CDN, If you are using Cloudflare or any CDN then check at what frequency the Cloudflare is fetching your website.
Cloudflare looks for the changes in the website and also for any threats so adjust the frequency of Cloudflare.
Below image is for my secondary website
If you are using websites like tools.pingdom / GTmetrix to check how much faster your website loads. Checking the website's speed is not wrong but do not do it very frequently. Always try to use the Google Page speed tool to avoid the problems.
Check whether your website(s) contains any practice pages, for example, My website is related to programming and automation testing. So I have provided some pages where people use automation tools to perform some tasks.
If your websites contain practice pages then make sure Google Analytics and Google Adsense code are not placed on those pages.
Check your Google analytics to see if you are receiving any users/bots are coming to your website. Sometimes spammers might ruin your websites by using bots.
There is also another kind of spam such as "website owners buying the traffic". If you have bought the traffic from spam websites then you might end up receiving the Warning.
You might have thought to improve your website ranking while buying the traffic but most of the time it does not help to improve the ranking.
Don't buy traffic from the Fiverr or Upwork.
I hope you are not clicking on the ads on your website if you are doing to then stop doing it.
One can use performance tools to create virtual users which may also cause this kind of issue because these tools will be considered as bots.
I am not sure whether these solutions work or not but try to use these methods only after a month only.
This what I am currently doing while I am facing the adlimit issues in the Adsense website. I will wait for one month then only I try to do something about it.
Patience is very important in this case
Meanwhile, you can send an email to the AdSense team but of the time they respond to our mail. When there a chance try it never hesitate to try.
Click on the feedback section, then it opens the below overlay, fill the details and screenshot in the overlay.
Try to delete existing ads on your AdSense and keep only auto ads. After deleting the ads, try to create new ad codes. To delete existing ads Go to Ads section on left side pane and you can see the list of ad codes at the bottom. Click the 3 dots and archive them then create new ads.
This is a stupid idea but may work. Try to delete your website from the list of your websites.
I still believe that AdSense is great, but the current incidence shows that you might want to have an alternative in place if the same thing happens in the future.
The following ad networks are a good AdSense alternative because they are also easy to implement, have no entry barrier, and are around for many years.