I opened an existing report with desktop version Power BI, and refreshed data. Got message Access to the resource is forbidden for data table using Google Analytics connector. Checked valid GA with correct access to Google Analytics online and set up and tested a second account, but same issue. Tested accounts access via https://ga-dev-tools.appspot.com/query-explorer/ and it worked fine, so seems issue could be with Power BI or connector rather than Google.
This issue has occured in the past as a temporary issue: