The AX1800 has a known driver conflict with 5GHz Guest mode when using WPA3 or 160MHz bandwidth.
The AX1800’s DHCP server may fail to assign IPs to guests. create guest network on xiaomi mi router ax1800 fixed
On the Xiaomi AX1800, return to the Wi-Fi Settings page in the web interface. Look for "Guest Network Privileges" or "Network Isolation" . Ensure the checkbox "Allow guests to access internal network resources" is UNCHECKED . The AX1800 has a known driver conflict with