I had that same problem when I got Alexa but after persistence and practice, now I can do it with ease. Try to find a way to lighten the G on Google when pronouncing it. Something like ‘oogle. I do that sometime for hard words, for me it’s currently Ls and Ms but they change every now and then. EDIT: and if there’s a problem with the word “ok” as well, try connecting the two words to sound like “okoogle” with a light touch on the k. Hope it helps.