Configure Asus RT-AC88U to find Xiaomi Gateway in Home Assistant

Hello.
Im starting in the domotics world.

I have the Asus RT-AC88U router, and integrated the Xiaomi Gateway v2 in Home Assistant.
After some time or reboot the home assistant, the system not found the gateway never more.

2021-01-14 22:18:33 ERROR (Thread-5) [xiaomi_gateway] Unknown gateway ip 192.168.0.200
...
2021-01-14 22:25:14 ERROR (SyncWorker_3) [xiaomi_gateway] Cannot connect to Gateway

With a other router (TP-LINK) works right (alwais found it).

I readed differents toppics with some possible solutions, but not works for me.

Any especific configuration or any idea to fix this problem?

The home assistant and the gateway have static ip.

Thanks