Router behind OPNsense Firewall can't get internet access

[manzano]

Hi,
I've been running a second router (Lancom) behind me OPNsense firewall for routing purposes and too add another layer of firewall. The Lancom router has 4 ports, one is connected to the OPNsense and the other three are creating their own network with a DHCP client and everything.
The port on the Lancom which is connected to the OPNsense was previously configured as DSL/Internet to declare this port for the router to get the internet. OPNsense knows the IP of the Lancom as a gateway, and the three networks which are created by the Lancom all have internet access.
I now changed the port which ist connected to the OPNsense installation from DSL/Internet to Client mode which means that it is still getting a IP on that port but does not look at it as the internet access. When i now try to reach the internet from one of the Lancom networks it is no longer possible, so I'm wondering if the problem lays within OPNsense or if it is Lancom related since it previously worked.

The only idea that I have is that I'm missing some default routes in OPNsense which were previously handled by the Lancom due to the DSL mode.

Thanks in advance for the help

Manzano