The OpenID 2.0 shutdown timetable has been known for a while now giving details to let users know OpenID 2.0 for Google accounts is going away.
Developers are being reminded they should migrate to OpenID Connect by April 20, 2015. On March 23, 2015 there will be the grace period where devs using the openid_shutdown_ack parameter will come to an end. This means the auto-approval will be turned off for all apps.
Then come April 20, 2015 OpenID 2.0 will be shut down, when users visit they will see a static error page on all requests, which is why developers need to migrate before this date.
A few applications and sites use OpenID 2.0 for confirmation when you login, and to get to information that you’ve issued them authorization to get to. OpenID 2.0 has been superseded by OpenID Connect. Beginning April 20, 2015, OpenID 2.0 will no more work for Google Accounts.
It is best to visit the apps help center or you can contact its support team, if you are a dev using OpenID 2.0 then migrate to OpenID Connect soon as you can, to learn how to do this please visit here.
What are your views on migrating to OpenID Connect?