No visitors are shown in Matomo

Goodevening,

InfinityFree database created
Matomo installed with ‘Softaculous’
Website added
Tracking code pasted i the Nicepage program
Tagmanager used and also installed that code

Everything without errors.
But now, after hours, still no visitors are shown.
The only thing that is reported is: no valid certificate, so ‘https’ is not accepted.

The documentation doesn’t help me, so what now?
Anyone have a tip, a hint… or perhaps the solution for this - common - problem?

Yours sincerely,
Peter Zondervan

Ok go to the respective page which should have t