Firewall suddenly blocking Traffic within LanNet

[godlie]

hi,
i have an opnsense FW ( v.18.1.8 ), it was working quite nice, but today it suddenly blocks all traffic on Port 80 from an Host within my LAN Net to another Host within the same LAN Net.

Im getting quite a few denied by default rule log entries there.

i attachted 2 screens, can you help me plz ?

[ruffy91]

172.31.0.200 is sending response packets to your firewall instead of to .212.
The routing table/netmask of .200 is wrong, this has nothing to do with the firewall.