Thanks 'FLOOD'.
I don't wish to start my PC in safe mode, I just wish to temporarily disable the setting options in KTS which stops my Network Speed Checker from running.
In answer to your "Also please tell us:" questions, here are the answers:-
I have the latest Windows 10 Pro version with their latest update (10.0.18362) & build is 160101.0800.
KTS is a 30 day trial
Network Speed Test is the app that is installed by default with Windows 10 Pro.
"Service is unavailable" alert. Please see .jpg.
As stated previously, I can run NST when I totally disable KTS.