Centrino Ultimate N-6300 slow to connect to Wi-Fi network

Connection to a Wi-Fi network on my Ubuntu Linux laptop started failing intermittently after it was upgraded to 19.04. It would be established only after turning off and turning on the adapter many times. Things that I tried but that did not work include: disabling IPv6; disabling power-saving on the Wi-Fi adapter; disabling Bluetooth/Wi-Fi interference […]