If your iPhone can’t detect a specific 5GHz Wi-Fi network, it might be because your router’s security settings are causing it. Many routers have a feature called MAC address filtering, which lets or blocks devices based on their unique MAC addresses.
Your iPhone’s MAC address might not be in the router’s whitelist, preventing it from connecting to the 5GHz network. Alternatively, it might be in the blacklist, blocking access to that network.
Contact your service provider or the router installer to check the settings and confirm your iPhone’s MAC address is listed correctly. Provide them with your iPhone’s current MAC address by navigating to Settings > Wi-Fi, selecting the “i” icon next to your connected network, and locating the “Wi-Fi Address.”
If you have Private Wi-Fi Address enabled, inform the agency not to use your iPhone’s MAC address for filtering. Instead, use the Private Wi-Fi MAC address.
This issue seems to be related to the router’s configuration, not your iPhone.