The solution was: my fault. this new accesspoints weren´t set on a floor map. So I couldn´t see them unless the floor maps were unselected. The solution from the Meraki service:
Could You please deselect the floor plan? once I've done it, I saw all APs
It can be done on the Radio Settings page, top right corner of the map > click on the layout icons > select "none" under floor plan.