Daily Anonimous Contacts in Mautic is always lower than Unique Visits in Google Analytics

Product Support
1

Your software
My Mautic version is: v2.15.3
My PHP version is: 7.2
My Joomla version is: 3.9.14
My Mautic-Joomla Plugin version is: 1.0.0

Your problem
My problem is:
I feel that not all the users visiting my website are being tracked by Mautic. I check statistics daily and always the number of anonimous contacts in Mautic is lower than the unique visitors in Google Analytics

These errors are showing in the log:
No errors in log

Steps I have tried to fix the problem:
I have checked the documentation and read the article “Page hit tracking doesn’t work”, and followed the recomendation …
The tracking pixel is not configured correctly. You can confirm this by looking at the dev tools of your browser. While looking on the page you wish to track, open the dev tools (press F12), go to the Network tab and reload the page. You'll see all the requests which were made. Filter those requests to images only and find the mtracking.gif image. Does it have status 200? If not, the path to your Mautic instance is probably incorrect.
… and I cannot find any mtracking.gif in the network requests

After that I checked the pages source code and related to Mautic I just find the following javascript within de page code …

(function(w,d,t,u,n,a,m){w['MauticTrackingObject']=n;
    w[n]=w[n]||function(){(w[n].q=w[n].q||[]).push(arguments)},a=d.createElement(t),
    m=d.getElementsByTagName(t)[0];a.async=1;a.src=u;m.parentNode.insertBefore(a,m)
})(window,document,'script','https://mautic.heading2market.com/mtc.js','mt');

mt('send', 'pageview', {});

So please, I’ll be very gratefull guys if someone can help me to solve this issue

Thanks a lot in advance for your help

Joan