I tried to use the tracker proxy for some of my websites and went through the step-by-step implementaion but I see no data for the websites in my self-hosted Matomo.
I went through the implementation steps again to be sure that nothing is wrong, but found no issue. I implemented the tracking script with Google Tag Manager, but when I check my sites with Ghostery I see no Piwik / Matomo shown in the list of trackers.
May that be the problem? And how can I verify if the tracking code is loaded anyways?
The easiest way to check if Matomo tracking is working fine is opening the browsers developer tool and checking for errors in the console and checking if in the network tab two requests to Matomo (or in your case the cache) are made: One fetching the js, the other sending the data.