Mikrotick interrupts data traffic of static subnet

Greetigns

I have installed several MT systems with lvl4 license on few places. Recently i came accross to the follwoing problem.

The network diagram is presented in the picture below:

As you can see from the picture, there is a network with an embedded firewall that separates the WAN area from the LAN area . There are two computers with static IPs and those computers are configured to pass their traffic through that embedded firewall. Now, i waned to add mikrotik on that network and add two computers that will be served by MT in hotspot manner.

Those computers are DHCP configured and once they are powered on, indeed they are getting served by MT. Summarizing, the PCs served by MT hotspot are working properly.

The problem is:

The computers with the static IPs, the once that were already there, are getting blocked from MikroTik. When i try to access the web Interface of the ADSL modem (located on the WAN side of the network) via my web browser, mikrotik hotspot comes on. When i try to ping the adsl modem or trace route i see that my ping`s are going through the MT router and not by the embedded firewall.


Since the Computers with the Static IPs are configured to use the embedded firewall as a gateway, why mikrotik takes over the traffic towards the embedded firewall/router?

Thanks