We recently upgraded from exchange 2010 to 2016 and did a domain name change. Voicemail emails stopped when I switched the SMTP IP to the new MX box. If I change it back to the original MX box (still running) everything works fine. Our original exchange server was on Server 2008 and the new one is Server 2012. Does anyone know of any bugs with IP Office R9 and Exchange 2016?