Refreshing materialized views

Hi

I created some materialized views and set a group as owner. My problem is that I can't refresh the views. I get
"permissiondenied" even when using the postgres super user. If I change the owner to an ordinary user I still can't
refreshthe view as the owner or postgres. Only if I change owner to postgres am I able to refresh the view, but only as
thepostgres user. I've mainly tried with Pgadmin4 but also a few times with psql, and the database is installed as a
dockercontainer. Please help. 

cheers
HU