I can’t connect the Wi-Fi from my iPhone. Error is “Unable to join the network” if your network security is managed by Wi-Fi address (also known as “MAC Address”), you may need to turn off Private Wi-Fi Address or modify your network settings.
Do you have guest protect block all private IP feature or access control settings enabled in SSID settings ? Also, I would suggest to try disabling private Wi-Fi address feature on your iPhone for a test.
Link to how to disable private Wi-Fi address: