Hello @BuggerBrown,

Welcome to our community.

May I know if your network topology diagram is as follows:

ISP modem—router )))((( client devices

(Note: — stands for wired connection,)))((( stands for wireless connection )

What are the firmware and hardware versions of BE805 now?  Please refer to How to find the hardware and firmware version of my TP-Link device

Here are some troubleshooting steps that may help you:
• Reboot the router: Power off your router, wait a few seconds, and power it back on.
• Check your device's network connection: Ensure your PC or laptop is connected to the main Wi-Fi network of the router, not a guest network or another device.
• Use Incognito/Private mode: Open your browser in Incognito or Private mode and try logging in again.
• Try a different device: Since your iPhone works, try using another PC or tablet to see if the issue persists.

Note: Some TP-Link routers allow you to log in with a TP-Link ID if the router has been bound to one. The first TP-Link ID used to log in will be set as the Admin account.

If the suggestions above don't help, please consider resetting your router to factory settings and setting up a new admin password. If the problem only occurs on your PC/laptop and not your iPhone, it may be related to your browser, device settings, or network configuration.