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Archer C5400X – 5GHz2 Speed Drop, OpenVPN Instability, and LED Control Bugs

Archer C5400X – 5GHz2 Speed Drop, OpenVPN Instability, and LED Control Bugs

Archer C5400X – 5GHz2 Speed Drop, OpenVPN Instability, and LED Control Bugs
Archer C5400X – 5GHz2 Speed Drop, OpenVPN Instability, and LED Control Bugs
2025-10-09 09:15:25 - last edited a week ago
Tags: #Smart Connect #Network Connectivity #Firmware Update #VPN #Bugs
Model: Archer C5400X  
Hardware Version: V1
Firmware Version: 1.2.1 Build 20250928 rel.12879

Hi all,

I’ve been using the Archer C5400X since it first came out. Over the years I’ve upgraded my internet plan from 100 Mbps to 500 Mbps, and recently I started noticing a few problems that still haven’t been fixed, even with the latest 2025 firmware.

1. 5GHz-2 speed drop
My router is placed in a small utility room, and my bedroom is directly opposite that wall.
The 5GHz-2 band is set to:

  • Channel 149

  • 80 MHz channel width

  • Transmit power: High

The signal strength is around -47 dBm, but sometimes the speed drops below 100 Mbps, and other times it can hit full speed (~480 Mbps).
5GHz-1 (channel 44, 80 MHz) always gives me full speed under the same conditions.
I usually keep Smart Connect on, but turning it off doesn’t make any difference — the issue is still there.

2. OpenVPN unstable
The built-in OpenVPN server keeps shutting down by itself. Sometimes it stops after a few hours, sometimes after a reboot, or when I disconnect for a few hours I can’t connect back anymore.
I’m using TP-Link DDNS for the connection, and I’ve confirmed it’s not the cause of the issue.
TP-Link support already acknowledged the problem before, but there’s still no fix.

3. LED control bug
The LED on/off setting doesn’t stay after a reboot — even if I turn them off, they come back on after restarting.
The Tether app switch for LEDs also keeps resetting itself or turning back on randomly.

The 2025 firmware update was nice to see, but none of these bugs seem to be fixed yet.
Would be great if TP-Link staff or other users can confirm if these issues are known or if there’s any workaround.

Thanks.

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#1
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1 Accepted Solution
Re:Archer C5400X – 5GHz2 Speed Drop, OpenVPN Instability, and LED Control Bugs-Solution
2025-10-25 09:29:37 - last edited a week ago

Hello @dexterchock ,

Welcome to our community.

 

Did all three of the abnormalities you mentioned begin after the router firmware update?

First, the LED will light up again after a reboot, primarily because the status LED is a key indicator of the router's operating status. Lighting up after a reboot is normal.

Could it be that before the firmware update, even after a reboot, the LED lights would still be off during the LED schedule's off time?

 

If 5GHz-2 is unstable, you can just try switching to a different channel for comparison. For example, 5GHz-1 uses channel 44. You can try other channels for comparison tests. to Changing Channel and Channel Width on a TP-Link Router (new logo).

 

If the OpenVPN server connection is unstable, try reconfiguring it.

Nice to Meet You in Our TP-Link Community. Check Out the Latest Posts: △Pre-release Firmware for Archer AX50 Introduces New Parental Control Features and Enhancements △Introducing AI QoS: Elevate Your Gaming Experience on the Archer GE800 Gaming Router △Connect TP-Link Archer BE550 to Germany's DS-Lite (Dual Stack Lite) Internet via WAN △Tether KidShield Test Recruitment - Safeguarding Children's Online Experience If you found the post or response helpful, please click Helpful. If an answer solves your problem, click "Recommended Solution" so that others can benefit from it.
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Re:Archer C5400X – 5GHz2 Speed Drop, OpenVPN Instability, and LED Control Bugs-Solution
2025-10-25 09:29:37 - last edited a week ago

Hello @dexterchock ,

Welcome to our community.

 

Did all three of the abnormalities you mentioned begin after the router firmware update?

First, the LED will light up again after a reboot, primarily because the status LED is a key indicator of the router's operating status. Lighting up after a reboot is normal.

Could it be that before the firmware update, even after a reboot, the LED lights would still be off during the LED schedule's off time?

 

If 5GHz-2 is unstable, you can just try switching to a different channel for comparison. For example, 5GHz-1 uses channel 44. You can try other channels for comparison tests. to Changing Channel and Channel Width on a TP-Link Router (new logo).

 

If the OpenVPN server connection is unstable, try reconfiguring it.

Nice to Meet You in Our TP-Link Community. Check Out the Latest Posts: △Pre-release Firmware for Archer AX50 Introduces New Parental Control Features and Enhancements △Introducing AI QoS: Elevate Your Gaming Experience on the Archer GE800 Gaming Router △Connect TP-Link Archer BE550 to Germany's DS-Lite (Dual Stack Lite) Internet via WAN △Tether KidShield Test Recruitment - Safeguarding Children's Online Experience If you found the post or response helpful, please click Helpful. If an answer solves your problem, click "Recommended Solution" so that others can benefit from it.
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Re:Archer C5400X – 5GHz2 Speed Drop, OpenVPN Instability, and LED Control Bugs
2025-11-01 19:21:39

  @Joseph-TP 

 

Hi, thanks for the response.

 

Regarding the OpenVPN issue, this problem actually started long before the latest firmware — it’s been there since I bought the router. The OpenVPN server will run normally for a while, but after a few hours or after the router has been idle for some time, the connection fails completely.

 

Here’s what I’ve confirmed so far:

 

  • I’m using TP-Link DDNS, and the domain resolves correctly — so it’s not a DDNS issue.
  • The OpenVPN service itself stops responding after a few hours or after reboot, even though the router shows it as “enabled.”
  • Trying to reconnect gives TLS handshake failed or Connection timeout errors until I disable and re-enable the VPN server manually.
  • Reconfiguring or regenerating the .ovpn file makes no difference.
  • This happens across multiple firmware versions, including the latest 2025 release.

 

 

Could you please check if there’s any known issue with the OpenVPN daemon crashing or timing out after idle time on the C5400X?

If you need logs, I can provide them — but the behavior is 100% reproducible.

 

Thanks.

 

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#3
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Re:Archer C5400X – 5GHz2 Speed Drop, OpenVPN Instability, and LED Control Bugs
3 weeks ago

Hello @dexterchock ,

Thanks for getting back to me.

 

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 )

 

The tech team has been made aware of your case; they will likely contact you via email to continue troubleshooting. Please check your email inbox and confirm.

Nice to Meet You in Our TP-Link Community. Check Out the Latest Posts: △Pre-release Firmware for Archer AX50 Introduces New Parental Control Features and Enhancements △Introducing AI QoS: Elevate Your Gaming Experience on the Archer GE800 Gaming Router △Connect TP-Link Archer BE550 to Germany's DS-Lite (Dual Stack Lite) Internet via WAN △Tether KidShield Test Recruitment - Safeguarding Children's Online Experience If you found the post or response helpful, please click Helpful. If an answer solves your problem, click "Recommended Solution" so that others can benefit from it.
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