SWITCH LAN - LAN PROBLEM

Hello, I have a Fortigate 100F model 7.2.4 build firewall with two VDSL internet lines that we used with Bridge mode before. Now we use fiber internet with a DMZ connection. Without changing the Virtual Wan Link setting of the device, we made adjustments only on Wan 1, enabled it to exit via DMZ, and deleted the Wan 2 connection. There is no problem with our internet connection, but communication cannot be established between other networks such as the vlan switch lan we created in the interface and the network we actively use, even though we wrote the rules. When we assign a manual IP, we can access the network. Do you want to reset the device or do you know a solution? I tried Asymmetric Route but it didn't work. And in external connections, it cannot access the network without being connected to the network via VPN, RDP, SQL etc. ports. Modem DMZ and firewall settings are correct.