Errors when running "normal" Matomo and Tag Manager on one Site (V3.10.0)

When I run “normal” Matomo and Tag Manager an one Site, we have some errors in the tag manager:

  • The first tag is not getting to the matomo server (Not at all)
  • when some other tags are hit the error message “Error: A siteId must be given to add a new tracker” appears
  • in the preview-mode everything works fine
  • When I only run the Tag Manager it works fine too.
    What can be wrong?

Sorry, I have no idea what the problem could be but two persons contacted me today with the same error message “Error: A siteId must be given to add a new tracker”.

Hi Ronan, thanks for your answer. For us the problem was that we run “normal” Matomo an Tag-Manager on one same site and included both codes. I reported it too in the german forum (Bestehende Tracking in Tag Manager verwenden ).
We haven’t integrated the tag manager anymore (which is a pity ;-)) but this is how the basic function of matomo works reliably again. We will now try to use the normal Matomo plugin with JS to implement the taging.
Do you have another idea?