There does seem to be some sort of issue at Google's end lately, as we've been getting sporadic reports recently from various merchants regarding an "unsuccessful attempts to contact the notification callback URL" message from Google, which cannot be explained by incorrect integration settings nor anything at our end. At any rate, it appears to be something out of our hands.
The Mobo's great so far, still fine-tuning the arm-mount positioning, noticed my elbows getting a tad sore, so thinking perhaps it could use a wee bit of padding on top of the main armrest covers, but that's about all I could suggest -- sure beats my old homebrew setup! :^)