Matomo only tracks some visitors - net::ERR_CERT_COMMON_NAME_INVALID Failed to load resource piwik.js

Hello, I’m experiencing the following problem:

I got to work on a website that I did not build myself. There are three Domains, the live and test domains that are hosted on the same server and the dev domain that is hosted on a different server. Now tracking visitors (Matomo v. 3.4.0) works like a charm in dev and test, but on the live domain (which is naturally the most important one) only some of the visitors are tracked - My own visits are never tracked and don’t appear in the visitor log. So are the visits by my colleagues.
Now I suspect the problem lies within the following:
When i open the developer tools console on all three sites, only on the live-domain there is the following error:

Failed to load resource: net::ERR_CERT_COMMON_NAME_INVALID piwiksubdomain/piwik.js

So the piwik JavaScript File is not loaded, because of an error that is probably related to the fact that the live-domain is the only one of the three that uses HTTPS ?
Not all visitors seem to experience this problem, but some (including me) most certainly do.

This is how far I’ve come. Does anyone have suggestions how to fix this or experienced similar problems?

Thanks in advance.

It seems like the HTTPS isn’t set up correctly.

Please test the subdomain here:

I’ve checked it, it received an A. The only problem is, that this website loads the piwik.js from the piwik- subdomain - Which is not SSL secured and therefore now the website is market as an unsecure connection because it tries loads non-secure resources. I’ve tried to put force SSL into the config.ini but that doesn’t work. Do I need to get an extra cerificate for the piwik sub domain? i need to solve this as soon as possible


It is impossible to include non-https javascript in an https site, so you’ll need to setup https for the piwik subdomain.

Okay thank you a lot !