"Connection to AUT refused" when trying to launch or attach an Application, that is started on a device.
The device or the application on it is not reachable per TCP/IP.
This can be checked through the use of the Python Script below:
A simple call would look like this for example (the last folder can also be python2 or python):
/home/sueltmann/squish-for-qt-6.6.2/python3/python ConnectionTest.py --host 220.127.116.11 --port 5555
"C:\Users\sueltmann\Squish for Qt 6.6.2\python3\python.exe" ConnectionTest.py --host 18.104.22.168 --port 5555