network connection disconnects when use static routing to another network constantly .

Hi Sophos experts,

Now I have two gateways one is for internet other is for IDC as below.

Sophos XG (192.168.1.66)      Router (192.168.1.52)

                       PC (192.168.1.0/24)

Now XG has static routing for IDC as below

-IP/Netmask : 192.168.101.0/24

-Gateway : 192.168.1.52

-Interface : Port1 (192.168.1.66)

When I connect to IDC server over the Router (192.168.1.52) the connection is okay for few min (within Ping seq number 115) but the connection is disconnected after few min.

so I checked log on Firewall the firewall recored two denined logs as below.

First, (Connection is okay during occuring this log)

Log Comp : Invalid Traffic

Action : Denined

Firewall Rule : 0

Message : Invalid TCP state.

Second, (I get this log when the network disconnect)

Log Comp : Invalid Traffic

Action : Denined

Firewall Rule : 0

Message : Could not associate packet to any connection.

additional, If I use another network with another gateway on the firewall like 192.168.2.1 G/W I never get network disconnection. (It also follow static routing)

This problem occur under 192.168.1.0/24 network.

Can you please advise how to fix this problem?