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Repeat the test with sshd after unlocking the screen and before doing anything else. If that is successful then the network is still active, as mine remains at all times, even when the screen is locked. You may have to open the port for ssh in the firewall as well. Then after the screen locks, from your other laptop try to ssh into the other system. If sshd is not already active, try starting sshd while the screen is active sudo systemctl enable rvice followed by sudo systemctl start rvice. You have another laptop as well as the machine having a problem. Does that mean that you connect to the broadband wifi properly on initial login and it works until you allow the screen to lock? If so then it would not seem to be a network issue but instead related to something that happens in locking and unlocking the screen.
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