L2TP/IPSEC - Mobile Clients traffic from outside gets blocked by firewall

[dukeha]

Dear Users and Administrators,

I set up L2TP over IPSEC as described in the WIKI.
The tunnel gets established and the mobile client gets an IP address within the preset range.
The mobile client can successfully send traffic out to the internet but traffic from outside back inside gets blocked by the firewall.
The firewall log looks like this if I try to open google:

ACTION                                TIME              INTERFACE                SOURCE                    DESTINATION                PROTOCOL
block/1000000104        Jun 17 18:52:47          l2tp0                172.217.22.78              192.168.180.128              TCP:SA

• under the menu "Interface Assignment" all l2tp connections are listed as available network ports but I did not assign any

I tried several Firewall rules but non had a positive outcome.

I would be very happy if anyone has an Idea or solution for my headache???