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Warning of low WAN port speed

Warning of low WAN port speed

Warning of low WAN port speed
Warning of low WAN port speed
2026-02-21 23:35:50 - last edited 3 weeks ago
Tags: #Network Connectivity #Firmware Update #Feature Request
Model: Deco M5  
Hardware Version: V1
Firmware Version: 1.9.1

Since latest firmware upgrade I started getting the low WAN port speed warning, and the speed is only 94 Mbps even though I have 1 Gbps (all historic speed tests - last in April 2025 - have been at 780 Mbps or more).

I use the original cable supplied with the 3 piece Deco box, which should be cat5e. And until recently worked in the same setup without any warning. Besides the main Deco M5 in version 1.0, I have 2 more M5 version 1.0 and 1 M5 ver 3.2.

Besides the reduced speed my Google Chromecast started loosing connection every few minutes. The Google Chromecast is 2 meters away from the main Deco and also this worked without issues for years until this happened.

 

Do I need to roll back to an old firmware? If so what version and where to get this?

 

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#1
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1 Accepted Solution
Re:Warning of low WAN port speed-Solution
2026-03-06 07:44:57 - last edited 3 weeks ago

  @ErikN 

Hi, thank you very much for the feedback.

It is also suggested to disable "Mesh Technology" for Chromecast, and change the IPV4 DNS to 8.8.8.8/8.8.4.4 to see whether it helps:

Later, if you'd like to spend a little more time, I could forward your case to the senior engineers to check whether they have any other suggestions.

Best regards.

▶Check What's Currently Going on With Deco ▶Deco Wi-Fi Heatmap ready for all Deco models
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Re:Warning of low WAN port speed
2026-03-03 03:35:56

  @ErikN 

Hi, thank you very much for your time and patience.

Have you tested with another new cable? There was some negative feedback about the Ethernet cables included in the package before. It's worth a try to replace the Ethernet cable.

I don't think there is a need to roll back the firmware.

Have you tried to set "Connection Preference" for the Chromecast to the main Deco+2.4Ghz to see whether it helps improve the stability?

 

Wait for your reply.

Best regards.

 

▶Check What's Currently Going on With Deco ▶Deco Wi-Fi Heatmap ready for all Deco models
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#2
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Re:Warning of low WAN port speed
2026-03-03 11:00:51

  @David-TP 

Thanks for your reply.

 

 I switched port on both router and Deco, and switched cable and restarted. This fixed the wan port low speed, and doing a speed test confirmed that I'm back to old speed.

 

BUT: the Chromecast disconnects still happen every 5-15 minutes.

 

Any suggestions?

 

/Erik

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#3
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Re:Warning of low WAN port speed
2026-03-04 01:32:13

  @ErikN 

Hi, I saw you mentioned there is also an ISP router. Did you set Deco M5 into "Access Point" mode?

Have you already set "Connection Preference" on the Chromecast?

It is also recommended to set "Address Reservation" for the Chromecast.

Then disable "Fast Roaming" and "Beamforming" on the Deco App>More>Advanced.

 

By the way, apart from the Chromecast, did you run into similar disconnection issues on other 2.4GHz devices?

Thank you very much.

Best regards.

 

 

▶Check What's Currently Going on With Deco ▶Deco Wi-Fi Heatmap ready for all Deco models
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#4
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Re:Warning of low WAN port speed
2026-03-04 16:03:38

  @David-TP 

 

Thanks.


Except that my Deco is in router mode I have the settings you suggest. ( I need the parental control).

 

First I had always 5GHz as I found articles suggesting that but later I switched to 2,4GHz as the issue persists.

 

I have not had other clients that have this issue. Even the TV (Sony Bravia) did never have this issue. I switched to the Chromecast because the TVs Android was getting to old for some streaming apps, about 1 year ago. And the issue only started recently.

 

/Erik
 

 

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#5
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Re:Warning of low WAN port speed-Solution
2026-03-06 07:44:57 - last edited 3 weeks ago

  @ErikN 

Hi, thank you very much for the feedback.

It is also suggested to disable "Mesh Technology" for Chromecast, and change the IPV4 DNS to 8.8.8.8/8.8.4.4 to see whether it helps:

Later, if you'd like to spend a little more time, I could forward your case to the senior engineers to check whether they have any other suggestions.

Best regards.

▶Check What's Currently Going on With Deco ▶Deco Wi-Fi Heatmap ready for all Deco models
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#6
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