Hello, I'm confident that I can help you to troubleshoot your issue with the SMTP server sending the voicemail e-mails. It can get tricky sometimes but I have a toolset that should allow us to identify the issue. I will also provide you with the know-how to setup your voicemail message for different scenarios (busy, unavailable, etc). I'm available to further discuss the project if you would like to. Thanks in advance. Best regards, Emanuel.