Track shop with Cross Domain Linking


I setup Matomo4 for an Ecommerce website “site1” which has a separate shop “site2”. We want to track the same visitor over both sites, so “site2” is an alias url for “site1” and Cross Domain Tracking is enabled as described here: The “pk_vid” is passed fine to “site2” and “site2” uses the same tracker code from “site1”.

However, no visits of “site2” are tracked in Matomo and I can’t see them in the behaviour menu. Do I need to setup another website for the shop with an individual tracker code? Do I need to set “site1” as alias url for “site2” then?

I also came across the Roll-Up plugin, but it doesn’t support Cross Domain Tracking. We want to see all data in one place in Matomo and a customer should be unique over both sites. Is that possible?