Hi Robert,
If it was a case where the ICMP, UDP and HTTPS passed, but other TCP e.g. HTTP and FTP not, then traffic policies etc could be looked at. I think the problem is lower down on the KVM virtual Interface/VLAN config level.
Can you dedicate a separate physical interface for lan0 and wan0? If not, perhaps test with tunnel mode.
Feel free to send the support query to support at wanos