The first UTM parameter in the URL is not tracked


I have a Marketing Campaigns Reporting activated on a Matomo On-Premise instance. In the config.ini.php there are the following configurations (same as in the documentation example):

campaign_name = “matomo_campaign,mtm_cpn,utm_campaign”
campaign_keyword = “mtm_keyword,matomo_kwd,mtm_kwd,utm_term”
campaign_source = “mtm_source,utm_source”
campaign_medium = “mtm_medium,utm_medium”
campaign_content = “mtm_content,utm_content”
campaign_id = “mtm_cid,utm_id,mtm_clid”
campaign_group = “mtm_group”
campaign_placement = “mtm_placement”

However, we have noticed that for some sessions the campaign source is missing (aka utm_source is not tracked). When testing the following UTM parameters attached to a URL this is what we see in the visits log and the same we get with the Reportings API:




It looks like the first parameter is consistently lost. There is nothing in the docu or issues about this problem, is there a bug or we have not installed something properly?

Hi there,

Have you got an example of the full URL you are using in the campaign link that we can check?
It doesn’t have to be your real domain, even if you replace the domain with