New finding: so when I installed resolvconf back, the DNS problems occured again, but now when I connect to VPN. After disconnecting, DNS worked properly again. So I removed resolvconf again and DNS problems disappeared :-) so maybe resolvconf causes this problem.
New finding: so when I installed resolvconf back, the DNS problems occured again, but now when I connect to VPN. After disconnecting, DNS worked properly again. So I removed resolvconf again and DNS problems disappeared :-) so maybe resolvconf causes this problem.