Only incoming traffic works, but no outgoing taffic

[danbet]

I tried to replace an existing firewall (SonicWall) with an OPNsense. Incoming connections worked, even with NAT, but outgoing connections did not work. I was unable to access a website, neither by name nor by IP address. No ping, no trace route worked. That irritates me, because I left the two predefined rules on the LAN interface as they were after the new installation.
Only the IP address of the LAN interface is assigned via DHCP, but permanently, controlled by the hardware address.
I do not understand that. It was the fourth OPNsense for me, the previous three worked. I don't see any differences in their configuration.

[chemlud]

How did you check for incoming traffic flowing?

Did you spoof the MAC of your old router/FW in the WAN interface settings of the opnsense?

[danbet]

How did you check for incoming traffic flowing?

Did you spoof the MAC of your old router/FW in the WAN interface settings of the opnsense?

Users have received new emails. No I do not spoof the MAC of the old router.