Unable to access Sophos firewall in Azure when a new interface is added.

Hi,

We have a vnet in azure with 2 address spaces 10.50.x.x and 10.90.x.x. We have deployed a sophos firewall there and added 2 subnets in 10.50.x.x as lan and wan networks. We also need to have 10.90.x.x network connected to the firewall. When we try to do that by adding a new network interface, we lose access to the firewall. If we remove that interface, the connection comes back up. Can you help us with this issue?

Thanks, Arosh.