Timeout error code received attempting to connect to a network

[Korporal]

I'm developing a purely managed code (.Net Core, C#) tool and class library that allows me to develop solid algorithms for the ESP8266 that I can then use to produce C or C++ code from later.

In my case the ESP8266 is connected to a small carrier USB board and connects to my PC, it appears as a COM port and my C# app can asynchronously communicate with the device over a serial port channel.

This works well and I can even get sustained TCP/IP data xfer running robustly for extended periods, over all this is a great way to leverage powerful languages and debug tools to fully get to grips with the device's behavior.

However I am seeing a problem when connecting to a WiFi network that is from a WiFi extender.

In my house are what appear as three SSID names call these MyNetwork, MyNetwork_2GEXT and MyNetwork_5GEXT.

The first is the main house router and the other two are exposed by the extender.

In my dev office the MyNetwork signal is weak but the ESP can connect to it and works well, it sometimes gets disconnected and I assume this is just because the signal may be weak. However the MyNetwork_2GEXT is far stronger but the ESP cannot connect to it, it gets CWJAP:1 every time, over and over.

Other devices (iPhones, TV sets) can connect to this easily (they can also connect to the 5G too but I know the ESP does not support that).

Now this is probably relevant, here's the version details of my devices:

This does seem old and so I want to update (I've ordered a different carrier that can do this easily).

But leaving that aside, is there anything that you guys can think of that explains my ability to connect to MyNetwork but not MyNetwork_2GEXT?