Dashoboard showing visitors but Visitors > Overview remains empty

Hi there

I just installed Matomo version: 4.1.0 (MySQL version: 5.7.31-34, PHP version: 7.2.34). The site being tracked is a vbulletin 5 forum. Tracking JS has been included into the header of the forum.

Looking at the Matomo dashboard, I can see visitors being tracked.
But drilling into the details, for instance, Visitors > Overview or Visitors > Devices, shows NOTHING:
Figures are 0 and graphs say: There is no data for this report.
Looking into the database, I can see data coming into tables such as matomo_log_visit or matomo_log_link_visit_action.

I ran the Systems Check and the only “error” is: Setup Cron (faster report loading)

Any help on this is appreciated!