@Maurits_1971 

 

I saw this happening when Deco M9 Plus has very old firmware, version 1.2.*. I can't tell if all devices connected to Main Deco is just a reporting issue or they indeed only connect to Main Deco, but problem usually goes away when Main Deco firmware is updated and it will be manual process, not through the Deco app. I can give you steps.

 

To make sure it is that issue and not something else, please post screenshot of Update Deco page from your Deco app, example:

 

  @Alexandre. thanks for the quick answer.
For some reason, it cvannot find my 2nd M9 anymore but this is what I have as firmware:

 

and this is the product code of both M9's:

 

I already foun the downloadpage for the firmware but I am afraid to instal Version 2.

  @Maurits_1971 

 

As I thought: firmware 1.2. Also, your M9 Plus is hardware version 2. Follow this document to upgrade your M9 Plus: How to Update the Firmware of Deco

Try Method 3 and if that does not work - try Method 2. 

 

Also, longer conversation on that topic I had with someone else can be found here: https://community.tp-link.com/en/home/forum/topic/636130

  @Alexandre. 

Hi,

Should I install all 3 (starting with the oldest) or only the newest one?

 

https://www.tp-link.com/nl/support/download/deco-m9-plus/v2/#Firmware

Start with the oldest. If successful, you will not need to use this method for next firmware upgrade: you can do it through Deco app. You are using this method only once. After that, it will be through "Update Deco" in Deco app.

  @Alexandre. 

 

Yes, it worked!

I have this equipment now for 3 years and did not realize it was not working correct.

 

Much more stable internet and streaming!

 

many thanks!!

  @Maurits_1971 

 

You are welcome. I also have Deco M9 Plus in my Deco mesh, so I am quite familiar with them. 

 

Two final recommendations:

 

1. If you haven't done it yet, visit Update Deco page in Deco app and update M9 Plus to latest firmware. You may be few iterations of firmware behind, so you might need to do it multiple times if Deco app won't update M9 Plus to the latest firmware in one step. The latest firmware for M9 Plus is 1.6.2.

 

2. Under Wi-Fi Settings, open settings for Main Network and under Security make sure it is WPA2. Not WPA or WPA/WPA2. If left as WPA, some devices (namely iPhones) may complain their WiFi connection is not sufficiently secure.