I'm using an Obi100 with Google voicemail. I have a Vtech DS6511 attached. Everything seems to work fine except the voicemail indicator on the phone. Regardless of whether I have voicemail or not, the phone's voicemail icon is "lit", it says "voicemail" on the screen, and when I call out I get a dial tone stutter.
If I actually have voicemail, I am able to access it fine. Otherwise, I get a recording that I have no voicemail even when the phone thinks I do.
Do I have something set wrong on the Obi100?
Other than this issue I think it is an impressive device.
Common problem (a.k.a "new user misunderstanding") and discussed and mentioned many, many times on here.
Search for GV and unread messages in Trash, Spam, folders. Clean out and/or mark those messages as read. Check that you are implementing this thing to your liking: GV Voicemail Notification & Missed Calls (http://www.obihai.com/FAQ.php#GV-VM-Notification-Missed-Calls).
Turns out I had 'Place missed calls in the inbox' checked. Unchecked it and deleted all Google email and that did the trick.
Thanks for your help and the link CoalMiner.