Auto-logon to KDE GUI has stopped working, having to manually launch

[Linux_newbie_no1]

A few days ago my laptop (Lenovo G580) stopped auto-logging on to the KDE desktop. Instead it boots to a command prompt for user ID and password, which I enter, after which I type startx at the command prompt, and then the computer boots into the KDE desktop fine. The only recent change I have made to the system is to add the line "wifi.powersave = 2" under the Device section of the NetworkManager.conf file (in an attempt to fix a wifi performance issue), which I can't imagine has caused this issue? I'm running Ubuntu 22.04.4 LTS.

[Linux_newbie_no1]

Also, when I open certain applications (e.g. Chrome) I get a pop-up saying: "The application Google Chrome has requested to open the wallet KDE wallet. Please enter the password for this wallet". Anyone know what's going on?