To ensure this works perfectly, do the following:
This is where most people mess up. You will see two checkboxes:
Did you know the Xiaomi Mi Router AX1800 actually supports guest networks? Yes.
One night, during a storm that knocked out the neighborhood’s main grid, the AX1800’s guest network glowed steady and strong. The family’s power‑bank‑charged lights were low, but through the guest SSID, the router connected the delivery driver who’d left earlier—Mira—so she could call her sister and say she’d be stuck but safe. The router, a humble gatekeeper, had become a bridge.
Your SSID length is too long. The main network SSID + Guest SSID combined must be less than 64 characters. Shorten your main Wi-Fi name to something under 20 characters, then try again.