@n1psu 

Hi,

When your PC can see the SSID of your phone's hotspot, then try the following.

In Windows 10 go to Settings -> Wi-Fi -> Manage known networks, click on the network name that corresponds to the SSID of your phone's hotspot and then click "Forget". Now connect to the hotspot again. Windows will ask you once more for the credentials of the Wi-Fi hotspot. This may or may not solve the "Can't connect to this network" problem.

Another thing I have come across myself is that the hotspot's Wi-Fi channel used by the phone may not be a "proper" one.

I own a smartphone that was sold to me as "EU version" and language and region are set to the EU country where I live. Yet, if I use the hotspot function and choose the 5 GHz band the phone will transmit on channels 149 to 161, which aren't to be used in the EU.

If the Windows drivers for the Wi-Fi card in the PC are restrictive and the channels used by the hotspot are outside of the legal range, then Windows may not show the SSID of the hotspot at all.

@woozle 
Thanks for the response!

Unfortunately your tip didn't work. Do you have some way to change the channel? I knew that there were some limitations in EU, but it is working well with my other family members. Idk why it's not working. Should I buy a new adapter or try to find the problem?

@n1psu 

You would have to check by youself if your phone allows for changing the channel of the hotspot.

I have checked on two phones that I own. On both you can only select the band (2.4 or 5 GHz), but not set a specific channel.

I suggest you first find out the channel of your phone's hotspot by running a Wi-Fi scanner app or program on one of your family member's devices.

If you are in the EU and the hotspot is transmitting on any channels from 36 to 144, then your T3U should actually be able to see it.

If it turns out the hotspot was indeed transmitting on channels 149 to 161, then go to the Device Manager in Windows and look if there is some region setting in the driver of your Archer T3U Wi-Fi adapter.

In case there is no such setting, then you could try if changing the region settings of Windows 10 itself to a country that allows using channels 149 to 161 (for example United States) would allow Windows to see your hotspot. The region settings of Windows 10 can be changed under Settings -> Time & language. Note that you may have to restart Windows after you change the region settings.

However, I don't know if changing the region of Windows will actually change anything with regards to the Wi-Fi card. This is merely something I would try if I had this problem.