Shutterfly Upload “Seamless Sign-in” support broken

Following code changes on Shutterfly’s servers, the Shutterfly Upload’s “Seamless Sign-in” functionality is broken. I’ve spoken to Shutterfly’s Level 2 support, and they’re looking into it. In the meantime, if you’re having problems, turn off the “Use Seamless Sign-in” option using the Lightroom Plug-in Manager (see the plug-in help for more information). Be sure to reload the plug-in, or restart Lightroom, to activate any configuration changes that you make!