Hi @Neki_AT 

You may refer to the following steps:
    1) Move the Mesh EAP closer to the uplink EAP;
    2) Avoid obstacles and wireless interference between the uplink EAP and mesh EAP;
    3) Change the channel of the uplink EAP, please test on different channels;
    4) Choose different uplink EAP units.
    5) Make sure the firmware version of the EAP and the controller are up-to-date.

  @Vincent-TP 

thx for your reply

AD 1) The "mesh top" is 5 meters away from the "mesh middle" (same floor). "Mesh middle"  "mesh below" is 2 meters away (staircase). It doesn't get any closer

AD 2) There is no interference betwenn the APs

AD 3) I can test it. Currently everything is set to automatic. 

AD 4) I already have, but it hasn't brought any improvement. The problem is also that the connection from "mesh below" to "mesh top" is not so good. That's why there is a mesh in between and connected as a chain

AD 5) The system is a few days old. All software is up to date

I did some tests yesterday. I noticed that when I connect a "problem device" directly to the "mesh below", I can reach it from all devices that are connected to the same AP. However, I cannot reach it from other APs or via cable. When I connect the same device to the "mesh top", I can reach it from all APs.

But not all devices have a problem. There are many devices on the AP that work without any issues. Any problematic device that I connect to the "mesh top" (although it has very poor reception) works then.

Could the problem be due to the channel?

Thx, Neki

Hi  @Neki_AT 

I believe so.

The performance of Mesh network is closely related to the wireless environment.

You may refer to the following guide to do some wireless optimization:

How to optimize wireless performance of EAP products

Hi,  @Vincent-TP 

Okay, I will go through this in detail. It's a bit overwhelming for me ;)

The AI WiFi Optimization unfortunately doesn't work because the APs are connected via WiFi. Do you know exactly what the software described there is called?

I have now -61dBM between the APs. I don't have the problem that an AP doesn't work at all, but that various devices can't communicate with the nearest AP. Shouldn't the mesh system forward the traffic?"

I have a device in the cellar that is 3 meters away from the "mesh below". The "mesh middle" and "mesh below" are very close, yet the "mesh middle" cannot reach the device in the cellar.

I don't understand it. :(

Thx, Neki

Hi,

I have now searched for the best channel with a Wifi scanner and changed it.

Unfortunately, this has not brought any improvement.

I have also tested connecting the AP via cable. I did this via tp-link Powerline PA7017 which I have at home. As soon as I plugged it in, all devices that were previously inaccessible were instantly accessible.

And now?

Thx, Neki

 Hi @Neki_AT 

The fact that the devices became accessible immediately when you connected the access point (AP) via powerline adapters (PA7017) suggests that there might be a problem with the wireless connection between the access points in your mesh network.  Floors or walls between different floors greatly weaken the wireless signal.

Did you try to set the Tx power to High?

If you already did that, we can say mesh is not quite suitable in this scenario.

Hi  @Vincent-TP ,

yes, I have already tried to set various values. According to your optimize link.
I think there is a general problem with tplink mesh and shelly. I find many people on the internet with the same problem. Also here: Shelly Plug S not connecting to EAP245v3 - Business Community (tp-link.com)

Unfortunately without a solution.

Maybe I can find a solution on the internet.

Thx, Neki

Hi  @Vincent-TP ,

can you explain the band steering option to me?
I have deactivated this and it seems to solve my problem. At least that's what it looks like. 

Could this have something to do with it?

thx, Neki

  @Vincent-TP 

thanks for all this information

br, Chris