as you are probably aware, Google is gradually shutting down their Google+ services.
In their recent announcement for developers they have stated, that Google+ API (which 3rd party apps like Postfity use for publishing to Google+) will be starting to intermittently fail as early as January 28, 2019.
Therefore this week (late January 2019) Postfity will be shutting down features related to Google+, including publishing to Google+ pages and connecting new Google+ accounts.
Google’s official statement:
We’re writing to let you know that as part of the sunset of the consumer version of Google+, we will be shutting down our Google+ APIs on March 7, 2019. As part of these changes, Google+ Sign-in has been fully deprecated and will also be shut down on March 7, 2019.
What do I need to know?
On March 7, 2019, all Google+ APIs and Google+ Sign-in will be shut down completely. This will be a progressive shutdown beginning in late January, with calls to these APIs starting to intermittently fail as early as January 28, 2019.