I have a new Samsung Galaxy S9 which replaces a Samsung Galaxy S6 and I have two issues which are probably connected:
a) I cannot use the App "Wifi File Transfer Pro" - when I launch the App on the phone it gives an IP address to enter into my browser on the PC, but when I enter this address it will not bring up the page - the connection eventually times out; on the Galaxy S6 this works perfectly
b) I have an app I have written in Java which has components running on the phone and my PC, which I use for transferring various files between the phone and my PC - again this has worked perfectly for many years on the Galaxy S6, but on the S9 it fails to connect: the phone component successfully wakes up the PC component which does its thing and then tries to connect to send the result, but the java command connection=new Socket(host, PORT) times out with the error message "java.net.ConnectionException: Connection timed out: connect"
It looks like a firewall issue, but it's not the firewall on my PC since I've tried disabling that temporarily. It may be a firewall issue on the Samsung S9 but I can't see how to configure that. I've tried tweaking the Setting "Phone visibility" but that doesn't seem to solve the issue.