How can I verify my account?

Niantic has removed the verify option since some weeks before it spun from Google. See the comment of Niantic in this post: "We've turned verification off."

Support page:

As of September 2015, we've removed the verification feature in Ingress, and it is no longer possible to receive the Verified Agent medal. All features that previously required verification will still work for new Agents that have never had the option to verify.

I'm now L7, and i never had the opportunity to verify.

ingress G+ said it's an error right now and they're working to fix it. Posted within the last 60 days.

they're working on it.