I got this error when trying to make a purchase: "RPC:S-7:AEC-0" (Google Play devices only)

Please read the explanation and possible resolution on this page: https://spryfox.zendesk.com/entries/70398490-I-got-this-error-when-trying-to-make-a-purchase-RPC-S-7-AEC-0-Google-Play-devices-only-