Make sure you are signed in your account when you use Cura (top right of your screen). If the blue button in the right bottom of your screen says “print via cloud” (after slicing) you are signed in.
When you are sure you are signed in, you should select your printer in the list (top left of your screen).
And then in the top middle of your screen you can select the configuration. If your printer has a Material Station, with multiple spools loaded, you should see multiple configurations to choose from.
if you select one of these configs, the print job should start without hiccup when you select “print via cloud”