Wireless Ethernet Bridge connection issue between 2x Asus RT-N18U

Hi!

I wanted to configure a wireless ethernet bridge connection between 2x Asus RT-N18U routers, but it was success only for a short time.

Primary router:
- Firmware: FreshTomato 2019.4
- IP address: 172.16.1.254/24, DHCP enabled
- Wireless mode: AP
- Wireless Network Mode: Auto
- SSID broadcast: yes
- Channel: 1, width: 20MHz
- Security: WPA2 Personal, AES
- Wireless filter: on, the MAC of secondary router is in the list
- Advanced - Routing - Misc. - Mode: Gateway
- Antenna: external...

Wireless Ethernet Bridge connection issue between 2x Asus RT-N18U