What's going on

When a TP-Link Wi-Fi router functions perfectly for your current devices but abruptly rejects new phones, laptops, or smart home plugs, the problem rarely means the router is entirely broken. Instead, the router's internal software is actively turning away the new hardware during the initial Wi-Fi handshake or IP assignment phase.

Most often, this happens because the router has run out of local IP addresses to hand out, or its internal firewall and security settings (like WPA3 or MAC filtering) are rejecting the new device's wireless chipset. Understanding whether the connection fails at the password validation step or the IP assignment step is key to resolving the issue quickly.

Symptoms people notice

• Existing devices browse normally, but any newly added device hangs on "Connecting..." or "Obtaining IP address..."
• The new client reports "Connected, no internet" and receives a self-assigned IP starting with 169.254.
• Entering the known-good Wi-Fi password prompts an instant "Incorrect Password" message on the new device.
• Smart home accessories (e.g., smart bulbs, cameras) fail to connect during setup because they cannot talk to a unified 2.4 GHz / 5 GHz SSID.
• The connection succeeds on the guest network but fails on the main primary network.

Likely causes

1. DHCP Lease Pool Exhaustion: The router's DHCP server has filled all available IP addresses in its assigned range due to long lease times or a narrow subnet pool.
2. Access Control / MAC Filtering: TP-Link's built-in security features or Tether app settings are blocking new hardware addresses from joining the network.
3. WPA3 / PMF Incompatibility: Newer TP-Link Archer and Deco units use WPA3 or Protected Management Frames (PMF), which older client Wi-Fi cards cannot process.
4. Smart Connect Confusion: Band steering combines 2.4 GHz and 5 GHz bands into one name; some legacy chips freeze when trying to negotiate which band to join.
5. Corrupted Router RAM: Stale network tables prevent new handshake requests until the system memory is rebooted.

Quick checks first

Before digging deep into system settings, try these quick steps:

• Test the Guest Network: Enable the TP-Link Guest Network without a password. If your new device joins easily, the root cause is a security protocol or DHCP constraint on your main network.
• Check the Tether App: Open the TP-Link Tether app, select your router, and look under client management to ensure the new device isn't accidentally paused or blacklisted.
• Toggle Flight Mode: Turn Airplane Mode on and off on the new device to reset its internal Wi-Fi radio before retrying.

If you're noticing broader connection issues across all devices, check our general router troubleshooting hub for network-wide solutions.

When it's a real hardware fault

If you perform a full factory reset (holding the rear Reset button for 10 seconds) and the router still refuses to assign IP addresses to new clients—or if the 2.4 GHz or 5 GHz status LEDs remain completely dark—you may be dealing with corrupted flash memory or a degraded radio module.

Overheating or sudden power spikes can permanently damage a router's radio chips. When this happens, client negotiation fails at the physical layer. If adjusting software settings yields no change, comparing hardware performance in our latest router reviews can help you decide on a reliable replacement.

Soft resets vs board/panel work

Software adjustments, DHCP configuration, and firmware updates are fast, non-destructive DIY tasks that solve the vast majority of new-device connection drops. Always exhaust soft resets and web panel adjustments first.

However, opening up a router chassis to repair circuit boards or micro-solder radio chips is rarely practical or economical for consumer networking gear. If clean firmware reboots and factory resets do not clear the issue, internal hardware component failure has likely occurred, requiring replacement rather than manual teardowns.

Next steps

1. Reboot everything: Cycle power on both your TP-Link router and modem.
2. Log into the admin portal: Access tplinkwifi.net or 192.168.0.1 in a web browser.
3. Adjust DHCP: Expand the pool range and reduce lease duration to 120 minutes.
4. Update Firmware: Go to Advanced > System Tools > Firmware Upgrade and install the latest patch.
5. Separate Wireless Bands: Turn off Smart Connect and create distinct 2.4 GHz and 5 GHz network names.