Hello  @Guineaman ,

Welcome to our community.

Since the red light indicates the router is unable to establish an internet connection through the upstream wireless network, here are some steps to try:

1. Reboot the router. Power it off, wait 10–15 seconds, then power it back on and allow it a minute or two to fully reconnect.
2. Change the DNS servers. Log in to the router's web management interface at http://tplinkwifi.net, then go to Advanced > Network > Internet > Advanced Settings, and set the DNS servers to 1.1.1.1 and 8.8.8.8. Sometimes the DNS assigned by the upstream network causes connectivity issues.
3. Try MAC cloning. Since your apartment's network may restrict connections based on MAC addresses, go to Advanced > Network > Internet > MAC Clone and clone the MAC address of a device that successfully connects to the building's network (e.g., your PC or phone). This can sometimes resolve authentication issues with building-managed networks. For detailed instructions, refer to: How to Configure MAC Address Clone on a TP-Link Archer Router
4. Check for firmware updates. In the web interface, go to Advanced > System > Firmware Update and make sure your router is running the latest firmware.

One important thing to be aware of: some apartment-managed networks use captive portals (a login page that appears when you first connect) or client isolation, which can prevent a router from authenticating properly even with the correct credentials. If the building's network requires you to accept terms or log in via a browser page, the travel router may not be able to complete that step automatically. In that case, you may need to contact your building's network administrator to ask whether routers/NAT devices are permitted on their network, or if your router's MAC address can be whitelisted.