Cannot get app tethering working when using usb cable from cellphone to laptop

[JohnLM 14]

I am successfully app tethering from a delphi 12.0 win10 tablet to a delphi 11.2 win10 laptop over wifi through a small portable mini wifi hotspot. 

(The device is a mini router hotspot with internet. However, the 'internet' service was cancelled years ago, but the wifi router portion works fine and I can connect via app tethering with this device successfully and without the worry of being hacked over internet since there is no internet on this device.) 

Also, I have successfully app tethered with these two (win10 tablet and laptop) in the past over the wifi when I had a working wifi/bluetooth chip in the win7 laptop.  However, that chip no longer works so no wifi and no internet on the win7 laptop.  

But, to get around this, I have discovered that I can get internet on it if I connect my cellphone to it through usb and set my phone to 'app tether'. And this has been and still is working for me for the last 6 months. 

This past week or so, I decided I need to start transferring some files and other things over from the win7 laptop to my other devices via app tethering but I am failing with the software connecting to the win7 laptop. 

 

The way I have the win10 tablet and win10 laptop and win7 laptop to the mini wifi router: 

1. In each device, I set the wifi to point to the mini wifi hotspot router. 
2. finished

 

And, the way I have the win10 table and win10 laptop and win7 laptop software setup is as follows: 

1. D12   win10 tablet as the server -- tpro (Shared) 
2. d11.2 win10 laptop as the client -- tpro (Mirror) 
3. xe7   win7 laptop as the client  -- tpro (Mirror) 

When I run all three software and begin with the win10 tablet as the server, it finds and connects with the win10 laptop, but not with the win7 laptop.  And I can pass text over to the win10 laptop. 

I believe the issue has something to do with using the proper IP address on the cellphone and/or on the laptop or, I have to set things up so that it reads the cellphones IP addres and then the laptops IP addres in order to connect. But since I know nothing about networking, I am clueless how to get this part working for the win7 laptop over usb to cellphone for app tethering. 

Does anyone here know how I can configure these two software for the server part (win10 tablet), and the win7 laptop ? 

(I will be sending text and files from the win7 laptop, so I will have that as the server too.)