@Augratin Here's the difference between router mode and AP mode. If you leave AX55 in router mode in this configuration, it will work but will introduce a double NAT in your network. If that's not a...

@Viniraptor If an old switch works in place of TL-SG1016D, then something's wrong with the TL-SG1016D. If that's the case better contact your retailer or your local support for assistance.

@Viniraptor In theory you should be able to do that. Is that the router you're using (cable gateway): If your router is configured in bridge mode it could lead to this behaviour. The other reason...

@Viniraptor Actually you can use the switch behind a router, but the DHCP server is on your router, not on the switch. Describe your network topology and your router make and model.

@SylwjJ If I don't care about the speed I would bet on Archer C54.

@Viniraptor TL-SG1016D is a unmanaged 16 port switch - it doesn't have a DHCP server. Usually the routers have a DHCP server.