@DjDocGaming Yes, that's possible - to check that compare your AX10 WAN IP address and your public IP address. If they are different then that's the case and you're probably behind double NAT or...

@DjDocGaming Here's a video guide and two case scenario for setting up an Open VPN on a TP-Link router.

@ChristianFJR Here are the instructions for factory reset a TP-Link device.

@rajat26 Which FW version do you have on the router ? Last FW version was released a year ago. Have you tried to use a different browser to open the router WebGUI ? Or maybe using an InPrivete window...

@arvind_r_2509 The Archer C5 v4 is a router ususally provided by ISPs. So it's quite possible that it doesn't support a VPN Server feature like this: If you don't have suche menu then you can't use...

@tenderfoot Beware when using whitelisting for Access Control - your wireless devices may use a randomized MAC address every time when they connect to your wireless network - details.