Why does PlusClient.loadPeople fail with HTTP 403 error?

Question

I have the old Google Plus (aka Google Play Service) API integrated into my app, and now I\'m trying to update things to use the V2 API which includes, among other things, a

Answer 1

make sure you have added the google+ api access. and client key created with SHA1 and complete project package in android manifest file

Answer 2

Did you register your digitally signed .apk file's public certificate in the Google APIs Console? If not, you can find instructions on how to do it here.