Issues with Tracking Custom Dimensions

Dear all,

my goal is to track the content of a css class. I have already created a variable to “read” the content of the specific css class. Also I have created a HTML tag with the following content:

{{Post-Author Variable}} being the variable I created before. The trigger for the tag is page view. I can see that the variable can be read in the debug/preview mode. However, it is not pushed to the dashboard of Matomo and I do not understand where the problem is. Do you have any suggestions?

Best regards and many thanks in advance,