I confirm. Same problem here with Pro. Google just blocks it with new site and service.
My site was setup on private VSP and IP is not shared with anyone.
Translate APi is no longer free according to Google. Google will still translate sites on-the-fly mode for free.
For now if you sign up for google cloud APi service you'll get 300$ for 2 months to try. So i did, i've got my Google API key, put it in plugin settings and everything works perfectly.
I had an answer from tech support stating that translation may not work due to many requests and crawlers but as i said Pro version without API key would not just work less API key even or brand new everything.
I was also offered to pay the difference between 1 year of enterprice service and a Pro license.
It seems not really fair. Some customers being offered free year of service in exchange for upgrade other don't.
And if Pro confirmed dead it should not even be advertised as it would work without API key in the first place...