I have read more on the topic and understand that the underlying issue is that Netflix are cracking down on users accessing geo-blocked content. Apparently Netflix announced already in 2016 it would be cracking down on users who use VPNs to access content available outside their own country. This is strange because my VPN was only blocked recently. There is now even a market for a special
VPN services because of this cat-and-mouse game between Netflix and VPN providers.