It seems that My Mazda cannot be accessed anymore, at least on pc/laptop?
You need an app on Android or Apple, that is only on smartphones.
Quote from Mazda UK :
With the introduction of connected services* to MyMazda we have launched a new version of the MyMazda App to provide you with a carefree and enhanced ownership experience. To achieve this new level of service and comfort, the MyMazda web log-in is no longer available, and has been replaced by the new MyMazda App.
I am not very pleased with this new approach.